166154421 has 4 divisors (see below), whose sum is σ = 221539232. Its totient is φ = 110769612.

The previous prime is 166154407. The next prime is 166154431. The reversal of 166154421 is 124451661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 166154421 - 2¹⁸ = 165892277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166154431) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27692401 + ... + 27692406.

It is an arithmetic number, because the mean of its divisors is an integer number (55384808).

Almost surely, 2^166154421 is an apocalyptic number.

It is an amenable number.

166154421 is a deficient number, since it is larger than the sum of its proper divisors (55384811).

166154421 is an equidigital number, since it uses as much as digits as its factorization.

166154421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55384810.

The product of its digits is 5760, while the sum is 30.

The square root of 166154421 is about 12890.0900307174. The cubic root of 166154421 is about 549.7568302450.

The spelling of 166154421 in words is "one hundred sixty-six million, one hundred fifty-four thousand, four hundred twenty-one".