78257664 has 240 divisors, whose sum is σ = 254702448. Its totient is φ = 23887872.

The previous prime is 78257623. The next prime is 78257687. The reversal of 78257664 is 46675287.

78257664 is a `hidden beast` number, since 78 + 2 + 576 + 6 + 4 = 666.

It is a super-2 number, since 2×78257664² = 12248523949473792, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2115054 + ... + 2115090.

Almost surely, 2^78257664 is an apocalyptic number.

78257664 is a gapful number since it is divisible by the number (74) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78257664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127351224).

78257664 is an abundant number, since it is smaller than the sum of its proper divisors (176444784).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

78257664 is an equidigital number, since it uses as much as digits as its factorization.

78257664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87 (or 59 counting only the distinct ones).

The product of its digits is 564480, while the sum is 45.

The square root of 78257664 is about 8846.3361907628. The cubic root of 78257664 is about 427.7358255642.

The spelling of 78257664 in words is "seventy-eight million, two hundred fifty-seven thousand, six hundred sixty-four".