166561426 has 4 divisors (see below), whose sum is σ = 249842142. Its totient is φ = 83280712.

The previous prime is 166561411. The next prime is 166561433. The reversal of 166561426 is 624165661.

166561426 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in only one way, i.e., 136913401 + 29648025 = 11701^2 + 5445^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41640355 + ... + 41640358.

Almost surely, 2^166561426 is an apocalyptic number.

166561426 is a deficient number, since it is larger than the sum of its proper divisors (83280716).

166561426 is an equidigital number, since it uses as much as digits as its factorization.

166561426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83280715.

The product of its digits is 51840, while the sum is 37.

The square root of 166561426 is about 12905.8678902273. The cubic root of 166561426 is about 550.2053514183.

The spelling of 166561426 in words is "one hundred sixty-six million, five hundred sixty-one thousand, four hundred twenty-six".