644947749446 has 64 divisors (see below), whose sum is σ = 1304091726336. Its totient is φ = 231024960000.

The previous prime is 644947749403. The next prime is 644947749491.

644947749446 is nontrivially palindromic in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 139235 + ... + 1144238.

It is an arithmetic number, because the mean of its divisors is an integer number (20376433224).

Almost surely, 2^644947749446 is an apocalyptic number.

644947749446 is an abundant number, since it is smaller than the sum of its proper divisors (659143976890).

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

644947749446 is a wasteful number, since it uses less digits than its factorization.

644947749446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1283757.

The product of its digits is 585252864, while the sum is 68.

The spelling of 644947749446 in words is "six hundred forty-four billion, nine hundred forty-seven million, seven hundred forty-nine thousand, four hundred forty-six".