644715786363 has 16 divisors (see below), whose sum is σ = 941973666816. Its totient is φ = 388984652640.

The previous prime is 644715786353. The next prime is 644715786467. The reversal of 644715786363 is 363687517446.

It is not a de Polignac number, because 644715786363 - 2⁸ = 644715786107 is a prime.

It is a super-2 number, since 2×644715786363² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 644715786297 and 644715786306.

It is not an unprimeable number, because it can be changed into a prime (644715786353) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43797220 + ... + 43811937.

It is an arithmetic number, because the mean of its divisors is an integer number (58873354176).

Almost surely, 2^644715786363 is an apocalyptic number.

644715786363 is a deficient number, since it is larger than the sum of its proper divisors (297257880453).

644715786363 is a wasteful number, since it uses less digits than its factorization.

644715786363 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87609394.

The product of its digits is 60963840, while the sum is 60.

The spelling of 644715786363 in words is "six hundred forty-four billion, seven hundred fifteen million, seven hundred eighty-six thousand, three hundred sixty-three".