664838021376 has 81 divisors (see below), whose sum is σ = 1917004767951. Its totient is φ = 221599627776.

The previous prime is 664838021359. The next prime is 664838021417. The reversal of 664838021376 is 673120838466.

The square root of 664838021376 is 815376.

It is a perfect power (a square), and thus also a powerful number.

664838021376 is a `hidden beast` number, since 6 + 6 + 48 + 380 + 213 + 7 + 6 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 39129555 + ... + 39146541.

Almost surely, 2^664838021376 is an apocalyptic number.

664838021376 is the 815376-th square number.

It is an amenable number.

664838021376 is an abundant number, since it is smaller than the sum of its proper divisors (1252166746575).

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

664838021376 is an frugal number, since it uses more digits than its factorization.

664838021376 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33996 (or 16992 counting only the distinct ones).

The product of its (nonzero) digits is 6967296, while the sum is 54.

The spelling of 664838021376 in words is "six hundred sixty-four billion, eight hundred thirty-eight million, twenty-one thousand, three hundred seventy-six".