166931491 has 2 divisors, whose sum is σ = 166931492. Its totient is φ = 166931490.

The previous prime is 166931489. The next prime is 166931573. The reversal of 166931491 is 194139661.

It is a happy number.

166931491 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 166931491 - 2¹ = 166931489 is a prime.

It is a super-2 number, since 2×166931491² = 55732245374966162, which contains 22 as substring.

Together with 166931489, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (166931411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83465745 + 83465746.

It is an arithmetic number, because the mean of its divisors is an integer number (83465746).

Almost surely, 2^166931491 is an apocalyptic number.

166931491 is a deficient number, since it is larger than the sum of its proper divisors (1).

166931491 is an equidigital number, since it uses as much as digits as its factorization.

166931491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34992, while the sum is 40.

The square root of 166931491 is about 12920.1970186217. The cubic root of 166931491 is about 550.6125307990.

The spelling of 166931491 in words is "one hundred sixty-six million, nine hundred thirty-one thousand, four hundred ninety-one".