166205257 has 4 divisors (see below), whose sum is σ = 166242436. Its totient is φ = 166168080.

The previous prime is 166205251. The next prime is 166205261. The reversal of 166205257 is 752502661.

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

It can be written as a sum of positive squares in 2 ways, for example, as 37405456 + 128799801 = 6116^2 + 11349^2 .

It is a cyclic number.

It is not a de Polignac number, because 166205257 - 2²³ = 157816649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166205251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10794 + ... + 21187.

It is an arithmetic number, because the mean of its divisors is an integer number (41560609).

Almost surely, 2^166205257 is an apocalyptic number.

It is an amenable number.

166205257 is a deficient number, since it is larger than the sum of its proper divisors (37179).

166205257 is an equidigital number, since it uses as much as digits as its factorization.

166205257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37178.

The product of its (nonzero) digits is 25200, while the sum is 34.

The square root of 166205257 is about 12892.0617823527. The cubic root of 166205257 is about 549.8128917255.

The spelling of 166205257 in words is "one hundred sixty-six million, two hundred five thousand, two hundred fifty-seven".