166321651 has 4 divisors (see below), whose sum is σ = 167067712. Its totient is φ = 165575592.

The previous prime is 166321637. The next prime is 166321679. The reversal of 166321651 is 156123661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 166321651 - 2²⁷ = 32103923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166321601) 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 in 3 ways as a sum of consecutive naturals, for example, 372696 + ... + 373141.

It is an arithmetic number, because the mean of its divisors is an integer number (41766928).

Almost surely, 2^166321651 is an apocalyptic number.

166321651 is a deficient number, since it is larger than the sum of its proper divisors (746061).

166321651 is an equidigital number, since it uses as much as digits as its factorization.

166321651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 746060.

The product of its digits is 6480, while the sum is 31.

The square root of 166321651 is about 12896.5751655236. The cubic root of 166321651 is about 549.9412069386.

The spelling of 166321651 in words is "one hundred sixty-six million, three hundred twenty-one thousand, six hundred fifty-one".