644631136446 has 64 divisors (see below), whose sum is σ = 1411994198016. Its totient is φ = 194576421600.

The previous prime is 644631136441. The next prime is 644631136463.

644631136446 is nontrivially palindromic in base 10.

It is a super-3 number, since 3×644631136446³ (a number of 36 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 644631136395 and 644631136404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644631136441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22681681 + ... + 22710083.

It is an arithmetic number, because the mean of its divisors is an integer number (22062409344).

Almost surely, 2^644631136446 is an apocalyptic number.

644631136446 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

644631136446 is an abundant number, since it is smaller than the sum of its proper divisors (767363061570).

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

644631136446 is a wasteful number, since it uses less digits than its factorization.

644631136446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29757.

The product of its digits is 2985984, while the sum is 48.

The spelling of 644631136446 in words is "six hundred forty-four billion, six hundred thirty-one million, one hundred thirty-six thousand, four hundred forty-six".