166591903 has 2 divisors, whose sum is σ = 166591904. Its totient is φ = 166591902.

The previous prime is 166591877. The next prime is 166591937. The reversal of 166591903 is 309195661.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 166591903 - 2²¹ = 164494751 is a prime.

It is a super-2 number, since 2×166591903² = 55505724290322818, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166591003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83295951 + 83295952.

It is an arithmetic number, because the mean of its divisors is an integer number (83295952).

Almost surely, 2^166591903 is an apocalyptic number.

166591903 is a deficient number, since it is larger than the sum of its proper divisors (1).

166591903 is an equidigital number, since it uses as much as digits as its factorization.

166591903 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 43740, while the sum is 40.

The square root of 166591903 is about 12907.0485781994. The cubic root of 166591903 is about 550.2389077790.

The spelling of 166591903 in words is "one hundred sixty-six million, five hundred ninety-one thousand, nine hundred three".