64664244640 has 24 divisors (see below), whose sum is σ = 152769278340. Its totient is φ = 25865697792.

The previous prime is 64664244599. The next prime is 64664244641. The reversal of 64664244640 is 4644246646.

It can be written as a sum of positive squares in 2 ways, for example, as 58635653904 + 6028590736 = 242148^2 + 77644^2 .

It is a Smith number, since the sum of its digits (46) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (64664244641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 202075605 + ... + 202075924.

Almost surely, 2^64664244640 is an apocalyptic number.

It is an amenable number.

64664244640 is an abundant number, since it is smaller than the sum of its proper divisors (88105033700).

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

64664244640 is a wasteful number, since it uses less digits than its factorization.

64664244640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404151544 (or 404151536 counting only the distinct ones).

The product of its (nonzero) digits is 2654208, while the sum is 46.

The spelling of 64664244640 in words is "sixty-four billion, six hundred sixty-four million, two hundred forty-four thousand, six hundred forty".