644116161 has 16 divisors (see below), whose sum is σ = 930432384. Its totient is φ = 394001664.

The previous prime is 644116117. The next prime is 644116163. The reversal of 644116161 is 161611446.

It is not a de Polignac number, because 644116161 - 2⁶ = 644116097 is a prime.

It is a super-2 number, since 2×644116161² = 829771257722755842, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (644116163) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42936 + ... + 55961.

It is an arithmetic number, because the mean of its divisors is an integer number (58152024).

Almost surely, 2^644116161 is an apocalyptic number.

It is an amenable number.

644116161 is a deficient number, since it is larger than the sum of its proper divisors (286316223).

644116161 is a wasteful number, since it uses less digits than its factorization.

644116161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99080.

The product of its digits is 3456, while the sum is 30.

The square root of 644116161 is about 25379.4436700256. The cubic root of 644116161 is about 863.6174293812.

The spelling of 644116161 in words is "six hundred forty-four million, one hundred sixteen thousand, one hundred sixty-one".