157978 has 4 divisors (see below), whose sum is σ = 236970. Its totient is φ = 78988.

The previous prime is 157951. The next prime is 157991. The reversal of 157978 is 879751.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 879751 = 383 ⋅2297.

It can be written as a sum of positive squares in only one way, i.e., 110889 + 47089 = 333^2 + 217^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39493 + ... + 39496.

2¹⁵⁷⁹⁷⁸ is an apocalyptic number.

157978 is a deficient number, since it is larger than the sum of its proper divisors (78992).

157978 is an equidigital number, since it uses as much as digits as its factorization.

157978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78991.

The product of its digits is 17640, while the sum is 37.

The square root of 157978 is about 397.4644638204. The cubic root of 157978 is about 54.0586924713.

The spelling of 157978 in words is "one hundred fifty-seven thousand, nine hundred seventy-eight".