166051591 has 2 divisors, whose sum is σ = 166051592. Its totient is φ = 166051590.

The previous prime is 166051573. The next prime is 166051609. The reversal of 166051591 is 195150661.

It is a balanced prime because it is at equal distance from previous prime (166051573) and next prime (166051609).

It is a cyclic number.

It is not a de Polignac number, because 166051591 - 2¹⁷ = 165920519 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166051511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83025795 + 83025796.

It is an arithmetic number, because the mean of its divisors is an integer number (83025796).

Almost surely, 2^166051591 is an apocalyptic number.

166051591 is a deficient number, since it is larger than the sum of its proper divisors (1).

166051591 is an equidigital number, since it uses as much as digits as its factorization.

166051591 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8100, while the sum is 34.

The square root of 166051591 is about 12886.1006902787. The cubic root of 166051591 is about 549.6433952837.

The spelling of 166051591 in words is "one hundred sixty-six million, fifty-one thousand, five hundred ninety-one".