66666977531 has 16 divisors (see below), whose sum is σ = 84479854848. Its totient is φ = 51096679200.

The previous prime is 66666977513. The next prime is 66666977549. The reversal of 66666977531 is 13577966666.

It is an interprime number because it is at equal distance from previous prime (66666977513) and next prime (66666977549).

It is not a de Polignac number, because 66666977531 - 2¹⁰ = 66666976507 is a prime.

It is a super-2 number, since 2×66666977531² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66666917531) 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, 7092065 + ... + 7101458.

It is an arithmetic number, because the mean of its divisors is an integer number (5279990928).

Almost surely, 2^66666977531 is an apocalyptic number.

66666977531 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

66666977531 is a deficient number, since it is larger than the sum of its proper divisors (17812877317).

66666977531 is a wasteful number, since it uses less digits than its factorization.

66666977531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14193602.

The product of its digits is 51438240, while the sum is 62.

The spelling of 66666977531 in words is "sixty-six billion, six hundred sixty-six million, nine hundred seventy-seven thousand, five hundred thirty-one".