66168187931 has 4 divisors (see below), whose sum is σ = 66644218200. Its totient is φ = 65692157664.

The previous prime is 66168187913. The next prime is 66168187961. The reversal of 66168187931 is 13978186166.

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

It is a cyclic number.

It is not a de Polignac number, because 66168187931 - 2⁶ = 66168187867 is a prime.

It is a super-2 number, since 2×66168187931² (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 (66168187961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 238014926 + ... + 238015203.

It is an arithmetic number, because the mean of its divisors is an integer number (16661054550).

Almost surely, 2^66168187931 is an apocalyptic number.

66168187931 is a deficient number, since it is larger than the sum of its proper divisors (476030269).

66168187931 is a wasteful number, since it uses less digits than its factorization.

66168187931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 476030268.

The product of its digits is 2612736, while the sum is 56.

The spelling of 66168187931 in words is "sixty-six billion, one hundred sixty-eight million, one hundred eighty-seven thousand, nine hundred thirty-one".