66571931 has 2 divisors, whose sum is σ = 66571932. Its totient is φ = 66571930.

The previous prime is 66571919. The next prime is 66571933. The reversal of 66571931 is 13917566.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66571931 is a prime.

It is a super-2 number, since 2×66571931² = 8863643994137522, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 66571933, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66571933) 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 as a sum of consecutive naturals, namely, 33285965 + 33285966.

It is an arithmetic number, because the mean of its divisors is an integer number (33285966).

Almost surely, 2^66571931 is an apocalyptic number.

66571931 is a deficient number, since it is larger than the sum of its proper divisors (1).

66571931 is an equidigital number, since it uses as much as digits as its factorization.

66571931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34020, while the sum is 38.

The square root of 66571931 is about 8159.1623957365. The cubic root of 66571931 is about 405.2879748347.

The spelling of 66571931 in words is "sixty-six million, five hundred seventy-one thousand, nine hundred thirty-one".