78157042 has 4 divisors (see below), whose sum is σ = 117235566. Its totient is φ = 39078520.

The previous prime is 78157031. The next prime is 78157049. The reversal of 78157042 is 24075187.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 24075187 = 239 ⋅100733.

It can be written as a sum of positive squares in only one way, i.e., 53743561 + 24413481 = 7331^2 + 4941^2 .

It is a super-2 number, since 2×78157042² = 12217046428379528, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 78156989 and 78157007.

It is not an unprimeable number, because it can be changed into a prime (78157049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19539259 + ... + 19539262.

Almost surely, 2^78157042 is an apocalyptic number.

78157042 is a deficient number, since it is larger than the sum of its proper divisors (39078524).

78157042 is a wasteful number, since it uses less digits than its factorization.

78157042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39078523.

The product of its (nonzero) digits is 15680, while the sum is 34.

The square root of 78157042 is about 8840.6471482579. The cubic root of 78157042 is about 427.5524224669.

The spelling of 78157042 in words is "seventy-eight million, one hundred fifty-seven thousand, forty-two".