666556101 has 32 divisors (see below), whose sum is σ = 1007731200. Its totient is φ = 435352320.

The previous prime is 666556091. The next prime is 666556139. The reversal of 666556101 is 101655666.

It is not a de Polignac number, because 666556101 - 2⁵ = 666556069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666556171) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 291081 + ... + 293361.

It is an arithmetic number, because the mean of its divisors is an integer number (31491600).

Almost surely, 2^666556101 is an apocalyptic number.

It is an amenable number.

666556101 is a deficient number, since it is larger than the sum of its proper divisors (341175099).

666556101 is a wasteful number, since it uses less digits than its factorization.

666556101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2506 (or 2500 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 666556101 is about 25817.7477910061. The cubic root of 666556101 is about 873.5321680630.

The spelling of 666556101 in words is "six hundred sixty-six million, five hundred fifty-six thousand, one hundred one".