644566416860 has 96 divisors (see below), whose sum is σ = 1543769321472. Its totient is φ = 224622351360.

The previous prime is 644566416847. The next prime is 644566416931. The reversal of 644566416860 is 68614665446.

It is a junction number, because it is equal to n+sod(n) for n = 644566416796 and 644566416805.

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, 1087022 + ... + 1571861.

It is an arithmetic number, because the mean of its divisors is an integer number (16080930432).

Almost surely, 2^644566416860 is an apocalyptic number.

It is an amenable number.

644566416860 is an abundant number, since it is smaller than the sum of its proper divisors (899202904612).

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

644566416860 is a wasteful number, since it uses less digits than its factorization.

644566416860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2658963 (or 2658961 counting only the distinct ones).

The product of its (nonzero) digits is 19906560, while the sum is 56.

The spelling of 644566416860 in words is "six hundred forty-four billion, five hundred sixty-six million, four hundred sixteen thousand, eight hundred sixty".