166045591 has 4 divisors (see below), whose sum is σ = 166973400. Its totient is φ = 165117784.

The previous prime is 166045571. The next prime is 166045639. The reversal of 166045591 is 195540661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 195540661 = 8887 ⋅22003.

It is a cyclic number.

It is not a de Polignac number, because 166045591 - 2⁷ = 166045463 is a prime.

It is a super-2 number, since 2×166045591² = 55142276581078562, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 166045591.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166045571) 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 in 3 ways as a sum of consecutive naturals, for example, 463636 + ... + 463993.

It is an arithmetic number, because the mean of its divisors is an integer number (41743350).

Almost surely, 2^166045591 is an apocalyptic number.

166045591 is a deficient number, since it is larger than the sum of its proper divisors (927809).

166045591 is an equidigital number, since it uses as much as digits as its factorization.

166045591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 927808.

The product of its (nonzero) digits is 32400, while the sum is 37.

The square root of 166045591 is about 12885.8678791923. The cubic root of 166045591 is about 549.6367750518.

The spelling of 166045591 in words is "one hundred sixty-six million, forty-five thousand, five hundred ninety-one".