666556056501 has 8 divisors (see below), whose sum is σ = 888813990240. Its totient is φ = 444334413552.

The previous prime is 666556056479. The next prime is 666556056521. The reversal of 666556056501 is 105650655666.

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

It is not a de Polignac number, because 666556056501 - 2¹⁷ = 666555925429 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666556056521) 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, 9029811 + ... + 9103328.

It is an arithmetic number, because the mean of its divisors is an integer number (111101748780).

Almost surely, 2^666556056501 is an apocalyptic number.

It is an amenable number.

666556056501 is a deficient number, since it is larger than the sum of its proper divisors (222257933739).

666556056501 is a wasteful number, since it uses less digits than its factorization.

666556056501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18145395.

The product of its (nonzero) digits is 4860000, while the sum is 51.

The spelling of 666556056501 in words is "six hundred sixty-six billion, five hundred fifty-six million, fifty-six thousand, five hundred one".