666755531 has 6 divisors (see below), whose sum is σ = 721989900. Its totient is φ = 615466488.

The previous prime is 666755527. The next prime is 666755539. The reversal of 666755531 is 135557666.

It is not a de Polignac number, because 666755531 - 2² = 666755527 is a prime.

It is a super-2 number, since 2×666755531² = 889125876238183922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666755539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1972481 + ... + 1972818.

It is an arithmetic number, because the mean of its divisors is an integer number (120331650).

Almost surely, 2^666755531 is an apocalyptic number.

666755531 is a deficient number, since it is larger than the sum of its proper divisors (55234369).

666755531 is a wasteful number, since it uses less digits than its factorization.

666755531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3945325 (or 3945312 counting only the distinct ones).

The product of its digits is 567000, while the sum is 44.

The square root of 666755531 is about 25821.6097677895. The cubic root of 666755531 is about 873.6192780846.

The spelling of 666755531 in words is "six hundred sixty-six million, seven hundred fifty-five thousand, five hundred thirty-one".