78157431 has 48 divisors (see below), whose sum is σ = 133261440. Its totient is φ = 43623360.

The previous prime is 78157411. The next prime is 78157433. The reversal of 78157431 is 13475187.

78157431 is a `hidden beast` number, since 7 + 81 + 574 + 3 + 1 = 666.

It is not a de Polignac number, because 78157431 - 2⁶ = 78157367 is a prime.

It is a super-2 number, since 2×78157431² = 12217168041039522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78157433) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 69036 + ... + 70158.

It is an arithmetic number, because the mean of its divisors is an integer number (2776280).

Almost surely, 2^78157431 is an apocalyptic number.

78157431 is a deficient number, since it is larger than the sum of its proper divisors (55104009).

78157431 is a wasteful number, since it uses less digits than its factorization.

78157431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1196 (or 1193 counting only the distinct ones).

The product of its digits is 23520, while the sum is 36.

The square root of 78157431 is about 8840.6691488823. The cubic root of 78157431 is about 427.5531317978.

The spelling of 78157431 in words is "seventy-eight million, one hundred fifty-seven thousand, four hundred thirty-one".