644363110643455 has 32 divisors (see below), whose sum is σ = 914383076826240. Its totient is φ = 426513533644800.

The previous prime is 644363110643437. The next prime is 644363110643467. The reversal of 644363110643455 is 554346011363446.

It is not a de Polignac number, because 644363110643455 - 2²⁹ = 644362573772543 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 644363110643396 and 644363110643405.

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, 69508746 + ... + 78231655.

It is an arithmetic number, because the mean of its divisors is an integer number (28574471150820).

Almost surely, 2^{644363110643455} is an apocalyptic number.

644363110643455 is a deficient number, since it is larger than the sum of its proper divisors (270019966182785).

644363110643455 is a wasteful number, since it uses less digits than its factorization.

644363110643455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147744739.

The product of its (nonzero) digits is 37324800, while the sum is 55.

The spelling of 644363110643455 in words is "six hundred forty-four trillion, three hundred sixty-three billion, one hundred ten million, six hundred forty-three thousand, four hundred fifty-five".