664551561105423 has 144 divisors (see below), whose sum is σ = 1108639877529600. Its totient is φ = 382059534689280.

The previous prime is 664551561105407. The next prime is 664551561105449. The reversal of 664551561105423 is 324501165155466.

664551561105423 is a `hidden beast` number, since 6 + 6 + 4 + 5 + 5 + 1 + 561 + 1 + 0 + 54 + 23 = 666.

It is not a de Polignac number, because 664551561105423 - 2⁴ = 664551561105407 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 664551561105423.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664551561105323) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 2618042290 + ... + 2618296112.

It is an arithmetic number, because the mean of its divisors is an integer number (7698888038400).

Almost surely, 2^{664551561105423} is an apocalyptic number.

664551561105423 is a deficient number, since it is larger than the sum of its proper divisors (444088316424177).

664551561105423 is a wasteful number, since it uses less digits than its factorization.

664551561105423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 255622 (or 255602 counting only the distinct ones).

The product of its (nonzero) digits is 12960000, while the sum is 54.

The spelling of 664551561105423 in words is "six hundred sixty-four trillion, five hundred fifty-one billion, five hundred sixty-one million, one hundred five thousand, four hundred twenty-three".