78331257 has 48 divisors (see below), whose sum is σ = 125163792. Its totient is φ = 47001600.

The previous prime is 78331229. The next prime is 78331273. The reversal of 78331257 is 75213387.

78331257 is a `hidden beast` number, since 78 + 331 + 257 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 33454656 + 44876601 = 5784^2 + 6699^2 .

It is not a de Polignac number, because 78331257 - 2¹⁸ = 78069113 is a prime.

It is a super-2 number, since 2×78331257² = 12271571646400098, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78331207) 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, 571693 + ... + 571829.

It is an arithmetic number, because the mean of its divisors is an integer number (2607579).

Almost surely, 2^78331257 is an apocalyptic number.

It is an amenable number.

78331257 is a deficient number, since it is larger than the sum of its proper divisors (46832535).

78331257 is a wasteful number, since it uses less digits than its factorization.

78331257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 298 (or 295 counting only the distinct ones).

The product of its digits is 35280, while the sum is 36.

The square root of 78331257 is about 8850.4947319345. The cubic root of 78331257 is about 427.8698635562.

The spelling of 78331257 in words is "seventy-eight million, three hundred thirty-one thousand, two hundred fifty-seven".