644431043461165 has 32 divisors (see below), whose sum is σ = 776680681351680. Its totient is φ = 513305131622400.

The previous prime is 644431043461151. The next prime is 644431043461187. The reversal of 644431043461165 is 561164340134446.

It is not a de Polignac number, because 644431043461165 - 2⁵ = 644431043461133 is a prime.

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, 22780255341 + ... + 22780283629.

It is an arithmetic number, because the mean of its divisors is an integer number (24271271292240).

Almost surely, 2^{644431043461165} is an apocalyptic number.

It is an amenable number.

644431043461165 is a deficient number, since it is larger than the sum of its proper divisors (132249637890515).

644431043461165 is a wasteful number, since it uses less digits than its factorization.

644431043461165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39013.

The product of its (nonzero) digits is 9953280, while the sum is 52.

The spelling of 644431043461165 in words is "six hundred forty-four trillion, four hundred thirty-one billion, forty-three million, four hundred sixty-one thousand, one hundred sixty-five".