166125521 has 4 divisors (see below), whose sum is σ = 166171044. Its totient is φ = 166080000.

The previous prime is 166125517. The next prime is 166125529. The reversal of 166125521 is 125521661.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 125521661 = 467 ⋅268783.

It can be written as a sum of positive squares in 2 ways, for example, as 67897600 + 98227921 = 8240^2 + 9911^2 .

It is a cyclic number.

It is not a de Polignac number, because 166125521 - 2² = 166125517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166125529) 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, 16760 + ... + 24761.

It is an arithmetic number, because the mean of its divisors is an integer number (41542761).

Almost surely, 2^166125521 is an apocalyptic number.

It is an amenable number.

166125521 is a deficient number, since it is larger than the sum of its proper divisors (45523).

166125521 is an equidigital number, since it uses as much as digits as its factorization.

166125521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45522.

The product of its digits is 3600, while the sum is 29.

The square root of 166125521 is about 12888.9689657474. The cubic root of 166125521 is about 549.7249544884.

The spelling of 166125521 in words is "one hundred sixty-six million, one hundred twenty-five thousand, five hundred twenty-one".