666656051 has 2 divisors, whose sum is σ = 666656052. Its totient is φ = 666656050.

The previous prime is 666656041. The next prime is 666656057. The reversal of 666656051 is 150656666.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666656051 is a prime.

It is not a weakly prime, because it can be changed into another prime (666656057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333328025 + 333328026.

It is an arithmetic number, because the mean of its divisors is an integer number (333328026).

Almost surely, 2^666656051 is an apocalyptic number.

666656051 is a deficient number, since it is larger than the sum of its proper divisors (1).

666656051 is an equidigital number, since it uses as much as digits as its factorization.

666656051 is an evil number, because the sum of its binary digits is even.

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

The square root of 666656051 is about 25819.6834023967. The cubic root of 666656051 is about 873.5758278922.

The spelling of 666656051 in words is "six hundred sixty-six million, six hundred fifty-six thousand, fifty-one".