666566757 has 12 divisors (see below), whose sum is σ = 963690624. Its totient is φ = 443975400.

The previous prime is 666566741. The next prime is 666566783. The reversal of 666566757 is 757665666.

It is not a de Polignac number, because 666566757 - 2⁴ = 666566741 is a prime.

It is a super-2 number, since 2×666566757² = 888622483074994098, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666566707) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22869 + ... + 43082.

It is an arithmetic number, because the mean of its divisors is an integer number (80307552).

Almost surely, 2^666566757 is an apocalyptic number.

It is an amenable number.

666566757 is a deficient number, since it is larger than the sum of its proper divisors (297123867).

666566757 is a wasteful number, since it uses less digits than its factorization.

666566757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67080 (or 67077 counting only the distinct ones).

The product of its digits is 9525600, while the sum is 54.

The square root of 666566757 is about 25817.9541598478. The cubic root of 666566757 is about 873.5368229896.

The spelling of 666566757 in words is "six hundred sixty-six million, five hundred sixty-six thousand, seven hundred fifty-seven".