664838640564 has 24 divisors (see below), whose sum is σ = 1772903041728. Its totient is φ = 189953897280.

The previous prime is 664838640563. The next prime is 664838640607. The reversal of 664838640564 is 465046838466.

It is a junction number, because it is equal to n+sod(n) for n = 664838640498 and 664838640507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664838640563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3957372777 + ... + 3957372944.

It is an arithmetic number, because the mean of its divisors is an integer number (73870960072).

Almost surely, 2^664838640564 is an apocalyptic number.

It is an amenable number.

664838640564 is an abundant number, since it is smaller than the sum of its proper divisors (1108064401164).

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

664838640564 is a wasteful number, since it uses less digits than its factorization.

664838640564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7914745735 (or 7914745733 counting only the distinct ones).

The product of its (nonzero) digits is 79626240, while the sum is 60.

The spelling of 664838640564 in words is "six hundred sixty-four billion, eight hundred thirty-eight million, six hundred forty thousand, five hundred sixty-four".