666556000 has 96 divisors (see below), whose sum is σ = 1786730400. Its totient is φ = 242368000.

The previous prime is 666555997. The next prime is 666556003. The reversal of 666556000 is 655666.

It is an interprime number because it is at equal distance from previous prime (666555997) and next prime (666556003).

It is a super-2 number, since 2×666556000² = 888593802272000000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666556003) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36426 + ... + 51574.

It is an arithmetic number, because the mean of its divisors is an integer number (18611775).

Almost surely, 2^666556000 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666556000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (893365200).

666556000 is an abundant number, since it is smaller than the sum of its proper divisors (1120174400).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

666556000 is a wasteful number, since it uses less digits than its factorization.

666556000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15185 (or 15167 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 34.

The square root of 666556000 is about 25817.7458349872. The cubic root of 666556000 is about 873.5321239423.

The spelling of 666556000 in words is "six hundred sixty-six million, five hundred fifty-six thousand".