645213775504 has 45 divisors (see below), whose sum is σ = 1306966771299. Its totient is φ = 308545158240.

The previous prime is 645213775457. The next prime is 645213775519. The reversal of 645213775504 is 405577312546.

The square root of 645213775504 is 803252.

It is a perfect power (a square), and thus also a powerful number.

645213775504 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×645213775504² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 73894819 + ... + 73903549.

Almost surely, 2^645213775504 is an apocalyptic number.

645213775504 is the 803252-nd square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645213775504

645213775504 is an abundant number, since it is smaller than the sum of its proper divisors (661752995795).

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

645213775504 is an frugal number, since it uses more digits than its factorization.

645213775504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17516 (or 8756 counting only the distinct ones).

The product of its (nonzero) digits is 3528000, while the sum is 49.

Multiplying 645213775504 by its sum of digits (49), we get a square (31615474999696 = 5622764²).

The spelling of 645213775504 in words is "six hundred forty-five billion, two hundred thirteen million, seven hundred seventy-five thousand, five hundred four".