764686656 has 140 divisors (see below), whose sum is σ = 2400386868. Its totient is φ = 239874048.

The previous prime is 764686649. The next prime is 764686687. The reversal of 764686656 is 656686467.

764686656 is a `hidden beast` number, since 76 + 468 + 66 + 56 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 400640256 + 364046400 = 20016^2 + 19080^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 83790 + ... + 92466.

Almost surely, 2^764686656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 764686656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1200193434).

764686656 is an abundant number, since it is smaller than the sum of its proper divisors (1635700212).

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

764686656 is a wasteful number, since it uses less digits than its factorization.

764686656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8718 (or 8699 counting only the distinct ones).

The product of its digits is 8709120, while the sum is 54.

The square root of 764686656 is about 27652.9683036017. The cubic root of 764686656 is about 914.4525400195.

The spelling of 764686656 in words is "seven hundred sixty-four million, six hundred eighty-six thousand, six hundred fifty-six".