64640244 has 12 divisors (see below), whose sum is σ = 150827264. Its totient is φ = 21546744.

The previous prime is 64640243. The next prime is 64640263. The reversal of 64640244 is 44204646.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×64640244² = 8356722288759072, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64640243) 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, 2693332 + ... + 2693355.

Almost surely, 2^64640244 is an apocalyptic number.

It is an amenable number.

64640244 is an abundant number, since it is smaller than the sum of its proper divisors (86187020).

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

64640244 is a wasteful number, since it uses less digits than its factorization.

64640244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5386694 (or 5386692 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 30.

The square root of 64640244 is about 8039.9156711995. The cubic root of 64640244 is about 401.3294183886.

The spelling of 64640244 in words is "sixty-four million, six hundred forty thousand, two hundred forty-four".