644772277446 has 16 divisors (see below), whose sum is σ = 1406775878208. Its totient is φ = 195385538600.

The previous prime is 644772277397. The next prime is 644772277477.

644772277446 is nontrivially palindromic in base 10.

644772277446 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 644772277446.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4884638400 + ... + 4884638531.

It is an arithmetic number, because the mean of its divisors is an integer number (87923492388).

Almost surely, 2^644772277446 is an apocalyptic number.

644772277446 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

644772277446 is an abundant number, since it is smaller than the sum of its proper divisors (762003600762).

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

644772277446 is a wasteful number, since it uses less digits than its factorization.

644772277446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9769276947.

The product of its digits is 88510464, while the sum is 60.

The spelling of 644772277446 in words is "six hundred forty-four billion, seven hundred seventy-two million, two hundred seventy-seven thousand, four hundred forty-six".