644269800015 has 64 divisors (see below), whose sum is σ = 1182377940480. Its totient is φ = 332649192960.

The previous prime is 644269799983. The next prime is 644269800037. The reversal of 644269800015 is 510008962446.

644269800015 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644269800015 - 2⁵ = 644269799983 is a prime.

It is a super-2 number, since 2×644269800015² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 164880 + ... + 1147050.

It is an arithmetic number, because the mean of its divisors is an integer number (18474655320).

Almost surely, 2^644269800015 is an apocalyptic number.

644269800015 is a deficient number, since it is larger than the sum of its proper divisors (538108140465).

644269800015 is a wasteful number, since it uses less digits than its factorization.

644269800015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 982341 (or 982335 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 45.

The spelling of 644269800015 in words is "six hundred forty-four billion, two hundred sixty-nine million, eight hundred thousand, fifteen".