166166551 has 4 divisors (see below), whose sum is σ = 175941072. Its totient is φ = 156392032.

The previous prime is 166166543. The next prime is 166166587. The reversal of 166166551 is 155661661.

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 166166551 - 2³ = 166166543 is a prime.

It is a super-2 number, since 2×166166551² = 55222645342471202, 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 166166551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166166531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4887235 + ... + 4887268.

It is an arithmetic number, because the mean of its divisors is an integer number (43985268).

Almost surely, 2^166166551 is an apocalyptic number.

166166551 is a deficient number, since it is larger than the sum of its proper divisors (9774521).

166166551 is an equidigital number, since it uses as much as digits as its factorization.

166166551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9774520.

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

The square root of 166166551 is about 12890.5605386267. The cubic root of 166166551 is about 549.7702081378.

The spelling of 166166551 in words is "one hundred sixty-six million, one hundred sixty-six thousand, five hundred fifty-one".