664399362978 has 64 divisors (see below), whose sum is σ = 1598254318080. Its totient is φ = 203371305984.

The previous prime is 664399362971. The next prime is 664399363039. The reversal of 664399362978 is 879263993466.

664399362978 is a `hidden beast` number, since 66 + 439 + 9 + 3 + 62 + 9 + 78 = 666.

664399362978 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (664399362971) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2316426 + ... + 2587397.

It is an arithmetic number, because the mean of its divisors is an integer number (24972723720).

Almost surely, 2^664399362978 is an apocalyptic number.

664399362978 is an abundant number, since it is smaller than the sum of its proper divisors (933854955102).

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

664399362978 is a wasteful number, since it uses less digits than its factorization.

664399362978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4904040 (or 4904034 counting only the distinct ones).

The product of its digits is 634894848, while the sum is 72.

The spelling of 664399362978 in words is "six hundred sixty-four billion, three hundred ninety-nine million, three hundred sixty-two thousand, nine hundred seventy-eight".