644170357716164 has 12 divisors (see below), whose sum is σ = 1127451104495100. Its totient is φ = 322041470717568.

The previous prime is 644170357716161. The next prime is 644170357716169. The reversal of 644170357716164 is 461617753071446.

It can be written as a sum of positive squares in 2 ways, for example, as 410295732154564 + 233874625561600 = 20255758^2 + 15292960^2 .

It is a super-2 number, since 2×644170357716164² (a number of 30 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 644170357716097 and 644170357716106.

It is not an unprimeable number, because it can be changed into a prime (644170357716161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10927001969 + ... + 10927060920.

It is an arithmetic number, because the mean of its divisors is an integer number (93954258707925).

Almost surely, 2^{644170357716164} is an apocalyptic number.

It is an amenable number.

644170357716164 is a deficient number, since it is larger than the sum of its proper divisors (483280746778936).

644170357716164 is a wasteful number, since it uses less digits than its factorization.

644170357716164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21854070262 (or 21854070260 counting only the distinct ones).

The product of its (nonzero) digits is 71124480, while the sum is 62.

The spelling of 644170357716164 in words is "six hundred forty-four trillion, one hundred seventy billion, three hundred fifty-seven million, seven hundred sixteen thousand, one hundred sixty-four".