644270445 has 96 divisors (see below), whose sum is σ = 1386088704. Its totient is φ = 269568000.

The previous prime is 644270441. The next prime is 644270447. The reversal of 644270445 is 544072446.

644270445 is a `hidden beast` number, since 644 + 2 + 7 + 0 + 4 + 4 + 5 = 666.

It is not a de Polignac number, because 644270445 - 2² = 644270441 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644270441) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 535845 + ... + 537045.

It is an arithmetic number, because the mean of its divisors is an integer number (14438424).

Almost surely, 2^644270445 is an apocalyptic number.

644270445 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

644270445 is an abundant number, since it is smaller than the sum of its proper divisors (741818259).

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

644270445 is a wasteful number, since it uses less digits than its factorization.

644270445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1363 (or 1360 counting only the distinct ones).

The product of its (nonzero) digits is 107520, while the sum is 36.

The square root of 644270445 is about 25382.4830345654. The cubic root of 644270445 is about 863.6863774595.

The spelling of 644270445 in words is "six hundred forty-four million, two hundred seventy thousand, four hundred forty-five".