644018364252 has 18 divisors (see below), whose sum is σ = 1627935309728. Its totient is φ = 214672788072.

The previous prime is 644018364251. The next prime is 644018364257. The reversal of 644018364252 is 252463810446.

644018364252 is a `hidden beast` number, since 6 + 4 + 40 + 183 + 6 + 425 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (18).

It is a junction number, because it is equal to n+sod(n) for n = 644018364198 and 644018364207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644018364251) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8944699468 + ... + 8944699539.

Almost surely, 2^644018364252 is an apocalyptic number.

It is an amenable number.

644018364252 is an abundant number, since it is smaller than the sum of its proper divisors (983916945476).

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

644018364252 is a wasteful number, since it uses less digits than its factorization.

644018364252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17889399017 (or 17889399012 counting only the distinct ones).

The product of its (nonzero) digits is 1105920, while the sum is 45.

The spelling of 644018364252 in words is "six hundred forty-four billion, eighteen million, three hundred sixty-four thousand, two hundred fifty-two".