166875581 has 2 divisors, whose sum is σ = 166875582. Its totient is φ = 166875580.

The previous prime is 166875563. The next prime is 166875607. The reversal of 166875581 is 185578661.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 161544100 + 5331481 = 12710^2 + 2309^2 .

It is a cyclic number.

It is not a de Polignac number, because 166875581 - 2⁶ = 166875517 is a prime.

It is a super-2 number, since 2×166875581² = 55694919068175122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (156875581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83437790 + 83437791.

It is an arithmetic number, because the mean of its divisors is an integer number (83437791).

Almost surely, 2^166875581 is an apocalyptic number.

It is an amenable number.

166875581 is a deficient number, since it is larger than the sum of its proper divisors (1).

166875581 is an equidigital number, since it uses as much as digits as its factorization.

166875581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 403200, while the sum is 47.

The square root of 166875581 is about 12918.0331707269. The cubic root of 166875581 is about 550.5510521171.

The spelling of 166875581 in words is "one hundred sixty-six million, eight hundred seventy-five thousand, five hundred eighty-one".