666610665 has 16 divisors (see below), whose sum is σ = 1218945408. Its totient is φ = 304736256.

The previous prime is 666610663. The next prime is 666610667. The reversal of 666610665 is 566016666.

It is an interprime number because it is at equal distance from previous prime (666610663) and next prime (666610667).

It is not a de Polignac number, because 666610665 - 2¹ = 666610663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (666610663) 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, 3174232 + ... + 3174441.

It is an arithmetic number, because the mean of its divisors is an integer number (76184088).

Almost surely, 2^666610665 is an apocalyptic number.

It is an amenable number.

666610665 is a deficient number, since it is larger than the sum of its proper divisors (552334743).

666610665 is a wasteful number, since it uses less digits than its factorization.

666610665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6348688.

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

The square root of 666610665 is about 25818.8044843289. The cubic root of 666610665 is about 873.5560030703.

The spelling of 666610665 in words is "six hundred sixty-six million, six hundred ten thousand, six hundred sixty-five".