78307928 has 8 divisors (see below), whose sum is σ = 146827380. Its totient is φ = 39153960.

The previous prime is 78307921. The next prime is 78307937. The reversal of 78307928 is 82970387.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×78307928² = 12264263175306368, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78307921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4894238 + ... + 4894253.

Almost surely, 2^78307928 is an apocalyptic number.

It is an amenable number.

78307928 is a deficient number, since it is larger than the sum of its proper divisors (68519452).

78307928 is a wasteful number, since it uses less digits than its factorization.

78307928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9788497 (or 9788493 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 44.

The square root of 78307928 is about 8849.1766848674. The cubic root of 78307928 is about 427.8273825700.

The spelling of 78307928 in words is "seventy-eight million, three hundred seven thousand, nine hundred twenty-eight".