666556610 has 8 divisors (see below), whose sum is σ = 1199801916. Its totient is φ = 266622640.

The previous prime is 666556543. The next prime is 666556643. The reversal of 666556610 is 16655666.

It can be written as a sum of positive squares in 2 ways, for example, as 572214241 + 94342369 = 23921^2 + 9713^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33327821 + ... + 33327840.

Almost surely, 2^666556610 is an apocalyptic number.

666556610 is a deficient number, since it is larger than the sum of its proper divisors (533245306).

666556610 is a wasteful number, since it uses less digits than its factorization.

666556610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66655668.

The product of its (nonzero) digits is 194400, while the sum is 41.

The square root of 666556610 is about 25817.7576485643. The cubic root of 666556610 is about 873.5323904137.

The spelling of 666556610 in words is "six hundred sixty-six million, five hundred fifty-six thousand, six hundred ten".