644528706552 has 32 divisors (see below), whose sum is σ = 1790357518800. Its totient is φ = 214842902112.

The previous prime is 644528706551. The next prime is 644528706553. The reversal of 644528706552 is 255607825446.

644528706552 is a `hidden beast` number, since 6 + 4 + 4 + 5 + 2 + 87 + 0 + 6 + 552 = 666.

644528706552 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 an interprime number because it is at equal distance from previous prime (644528706551) and next prime (644528706553).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644528706551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1491964383 + ... + 1491964814.

Almost surely, 2^644528706552 is an apocalyptic number.

It is an amenable number.

644528706552 is an abundant number, since it is smaller than the sum of its proper divisors (1145828812248).

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

644528706552 is a wasteful number, since it uses less digits than its factorization.

644528706552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2983929212 (or 2983929202 counting only the distinct ones).

The product of its (nonzero) digits is 16128000, while the sum is 54.

The spelling of 644528706552 in words is "six hundred forty-four billion, five hundred twenty-eight million, seven hundred six thousand, five hundred fifty-two".