166937521 has 4 divisors (see below), whose sum is σ = 167323492. Its totient is φ = 166551552.

The previous prime is 166937497. The next prime is 166937531. The reversal of 166937521 is 125739661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 125739661 = 41 ⋅3066821.

It can be written as a sum of positive squares in 2 ways, for example, as 69639025 + 97298496 = 8345^2 + 9864^2 .

It is a cyclic number.

It is not a de Polignac number, because 166937521 - 2⁵ = 166937489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166937531) 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, 192336 + ... + 193201.

It is an arithmetic number, because the mean of its divisors is an integer number (41830873).

Almost surely, 2^166937521 is an apocalyptic number.

It is an amenable number.

166937521 is a deficient number, since it is larger than the sum of its proper divisors (385971).

166937521 is an equidigital number, since it uses as much as digits as its factorization.

166937521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 385970.

The product of its digits is 68040, while the sum is 40.

The square root of 166937521 is about 12920.4303720890. The cubic root of 166937521 is about 550.6191605718.

The spelling of 166937521 in words is "one hundred sixty-six million, nine hundred thirty-seven thousand, five hundred twenty-one".