660666651 has 32 divisors (see below), whose sum is σ = 979968000. Its totient is φ = 394007328.

The previous prime is 660666649. The next prime is 660666653. The reversal of 660666651 is 156666066.

It is an interprime number because it is at equal distance from previous prime (660666649) and next prime (660666653).

It is not a de Polignac number, because 660666651 - 2¹ = 660666649 is a prime.

It is not an unprimeable number, because it can be changed into a prime (660666653) 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, 100380 + ... + 106758.

It is an arithmetic number, because the mean of its divisors is an integer number (30624000).

Almost surely, 2^660666651 is an apocalyptic number.

660666651 is a deficient number, since it is larger than the sum of its proper divisors (319301349).

660666651 is a wasteful number, since it uses less digits than its factorization.

660666651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6503.

The product of its (nonzero) digits is 233280, while the sum is 42.

The square root of 660666651 is about 25703.4365601178. The cubic root of 660666651 is about 870.9518146849.

The spelling of 660666651 in words is "six hundred sixty million, six hundred sixty-six thousand, six hundred fifty-one".