78309057 has 16 divisors (see below), whose sum is σ = 109855872. Its totient is φ = 49553280.

The previous prime is 78308999. The next prime is 78309059. The reversal of 78309057 is 75090387.

It is not a de Polignac number, because 78309057 - 2⁷ = 78308929 is a prime.

It is a super-2 number, since 2×78309057² = 12264616816458498, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78309059) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4053 + ... + 13154.

It is an arithmetic number, because the mean of its divisors is an integer number (6865992).

Almost surely, 2^78309057 is an apocalyptic number.

It is an amenable number.

78309057 is a deficient number, since it is larger than the sum of its proper divisors (31546815).

78309057 is a wasteful number, since it uses less digits than its factorization.

78309057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17288.

The product of its (nonzero) digits is 52920, while the sum is 39.

The square root of 78309057 is about 8849.2404758827. The cubic root of 78309057 is about 427.8294386189.

The spelling of 78309057 in words is "seventy-eight million, three hundred nine thousand, fifty-seven".