166891225 has 6 divisors (see below), whose sum is σ = 206945150. Its totient is φ = 133512960.

The previous prime is 166891199. The next prime is 166891237. The reversal of 166891225 is 522198661.

It can be written as a sum of positive squares in 3 ways, for example, as 2359296 + 164531929 = 1536^2 + 12827^2 .

It is not a de Polignac number, because 166891225 - 2¹⁵ = 166858457 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3337800 + ... + 3337849.

Almost surely, 2^166891225 is an apocalyptic number.

It is an amenable number.

166891225 is a deficient number, since it is larger than the sum of its proper divisors (40053925).

166891225 is an equidigital number, since it uses as much as digits as its factorization.

166891225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6675659 (or 6675654 counting only the distinct ones).

The product of its digits is 51840, while the sum is 40.

The square root of 166891225 is about 12918.6386666707. The cubic root of 166891225 is about 550.5682556557.

The spelling of 166891225 in words is "one hundred sixty-six million, eight hundred ninety-one thousand, two hundred twenty-five".