644774487762 has 16 divisors (see below), whose sum is σ = 1289749885632. Its totient is φ = 214891344240.

The previous prime is 644774487761. The next prime is 644774487787. The reversal of 644774487762 is 267784477446.

It is a junction number, because it is equal to n+sod(n) for n = 644774487693 and 644774487702.

It is not an unprimeable number, because it can be changed into a prime (644774487761) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8329518 + ... + 8406569.

It is an arithmetic number, because the mean of its divisors is an integer number (80609367852).

Almost surely, 2^644774487762 is an apocalyptic number.

644774487762 is an abundant number, since it is smaller than the sum of its proper divisors (644975397870).

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

644774487762 is a wasteful number, since it uses less digits than its factorization.

644774487762 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16742513.

The product of its digits is 354041856, while the sum is 66.

The spelling of 644774487762 in words is "six hundred forty-four billion, seven hundred seventy-four million, four hundred eighty-seven thousand, seven hundred sixty-two".