166621031 has 2 divisors, whose sum is σ = 166621032. Its totient is φ = 166621030.

The previous prime is 166621019. The next prime is 166621069. The reversal of 166621031 is 130126661.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166621031 is a prime.

It is a super-2 number, since 2×166621031² = 55525135943005922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166623031) 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, 83310515 + 83310516.

It is an arithmetic number, because the mean of its divisors is an integer number (83310516).

Almost surely, 2^166621031 is an apocalyptic number.

166621031 is a deficient number, since it is larger than the sum of its proper divisors (1).

166621031 is an equidigital number, since it uses as much as digits as its factorization.

166621031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 166621031 is about 12908.1769045826. The cubic root of 166621031 is about 550.2709750136.

Adding to 166621031 its reverse (130126661), we get a palindrome (296747692).

The spelling of 166621031 in words is "one hundred sixty-six million, six hundred twenty-one thousand, thirty-one".