644395002 has 24 divisors (see below), whose sum is σ = 1347267264. Its totient is φ = 205458264.

The previous prime is 644395001. The next prime is 644395057. The reversal of 644395002 is 200593446.

It is a super-5 number, since 5×644395002⁵ (a number of 45 digits) contains 55555 as substring.

It is not an unprimeable number, because it can be changed into a prime (644395001) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 98338 + ... + 104685.

It is an arithmetic number, because the mean of its divisors is an integer number (56136136).

Almost surely, 2^644395002 is an apocalyptic number.

644395002 is an abundant number, since it is smaller than the sum of its proper divisors (702872262).

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

644395002 is a wasteful number, since it uses less digits than its factorization.

644395002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203074 (or 203051 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 33.

The square root of 644395002 is about 25384.9365175491. The cubic root of 644395002 is about 863.7420327892.

The spelling of 644395002 in words is "six hundred forty-four million, three hundred ninety-five thousand, two".