66688131 has 4 divisors (see below), whose sum is σ = 88917512. Its totient is φ = 44458752.

The previous prime is 66688129. The next prime is 66688133. The reversal of 66688131 is 13188666.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (66688129) and next prime (66688133).

It is not a de Polignac number, because 66688131 - 2¹ = 66688129 is a prime.

It is a super-2 number, since 2×66688131² = 8894613632546322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66688131.

It is not an unprimeable number, because it can be changed into a prime (66688133) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11114686 + ... + 11114691.

It is an arithmetic number, because the mean of its divisors is an integer number (22229378).

Almost surely, 2^66688131 is an apocalyptic number.

66688131 is a deficient number, since it is larger than the sum of its proper divisors (22229381).

66688131 is a wasteful number, since it uses less digits than its factorization.

66688131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22229380.

The product of its digits is 41472, while the sum is 39.

The square root of 66688131 is about 8166.2801201036. The cubic root of 66688131 is about 405.5236451724.

The spelling of 66688131 in words is "sixty-six million, six hundred eighty-eight thousand, one hundred thirty-one".