644534537562 has 24 divisors (see below), whose sum is σ = 1469991051360. Its totient is φ = 203537222280.

The previous prime is 644534537539. The next prime is 644534537597. The reversal of 644534537562 is 265735435446.

644534537562 is a `hidden beast` number, since 6 + 4 + 4 + 5 + 3 + 45 + 37 + 562 = 666.

It is a super-2 number, since 2×644534537562² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 644534537499 and 644534537508.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 942301614 + ... + 942302297.

It is an arithmetic number, because the mean of its divisors is an integer number (61249627140).

Almost surely, 2^644534537562 is an apocalyptic number.

644534537562 is an abundant number, since it is smaller than the sum of its proper divisors (825456513798).

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

644534537562 is a wasteful number, since it uses less digits than its factorization.

644534537562 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1884603938 (or 1884603935 counting only the distinct ones).

The product of its digits is 36288000, while the sum is 54.

The spelling of 644534537562 in words is "six hundred forty-four billion, five hundred thirty-four million, five hundred thirty-seven thousand, five hundred sixty-two".