5778

5778 is the natural number that follows 5777 and precedes 5779.

In mathematics, 5778 is an even composite integer with prime factorization 2 × 3^3 × 107. It is the 107th triangular number, since 107 × 108 / 2 equals 5778. The digits of 5778 sum to 27, making it a Harshad (Niven) number in base 10, because 5778 is divisible by 27 (5778 ÷ 27 = 214). It is also divisible by 9 (5778 ÷ 9 = 642) and by 54 (5778 = 54 × 107), among other divisors.

In calendar usage, 5778 is notable as a year designation in the Hebrew calendar. Hebrew year 5778 corresponds to roughly the civil years 2017–2018 CE, spanning from autumn 2017 to autumn 2018. The year is used in Jewish chronology to label religious and cultural periods within that span.

Fulfilling multiple numerical properties, 5778 also serves as an example of a triangular number, a Harshad number, and a member of the sequence of integers with mixed prime factors. Its factorization and triangular nature link it to common topics in elementary number theory, while its use as a calendar year illustrates how large integers intersect with history and culture.