644461155024623 has 8 divisors (see below), whose sum is σ = 658186247995392. Its totient is φ = 630736610116536.

The previous prime is 644461155024539. The next prime is 644461155024653. The reversal of 644461155024623 is 326420551164446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 644461155024623 - 2⁸ = 644461155024367 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644461155024653) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 134638415 + ... + 139342832.

It is an arithmetic number, because the mean of its divisors is an integer number (82273280999424).

Almost surely, 2^{644461155024623} is an apocalyptic number.

644461155024623 is a deficient number, since it is larger than the sum of its proper divisors (13725092970769).

644461155024623 is a wasteful number, since it uses less digits than its factorization.

644461155024623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274031341.

The product of its (nonzero) digits is 16588800, while the sum is 53.

The spelling of 644461155024623 in words is "six hundred forty-four trillion, four hundred sixty-one billion, one hundred fifty-five million, twenty-four thousand, six hundred twenty-three".