166525661 has 4 divisors (see below), whose sum is σ = 167586492. Its totient is φ = 165464832.

The previous prime is 166525651. The next prime is 166525673.

166525661 is nontrivially palindromic in base 10.

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 30360100 + 136165561 = 5510^2 + 11669^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166525661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166525651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 530180 + ... + 530493.

It is an arithmetic number, because the mean of its divisors is an integer number (41896623).

Almost surely, 2^166525661 is an apocalyptic number.

It is an amenable number.

166525661 is a deficient number, since it is larger than the sum of its proper divisors (1060831).

166525661 is a wasteful number, since it uses less digits than its factorization.

166525661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1060830.

The product of its digits is 64800, while the sum is 38.

The square root of 166525661 is about 12904.4822058074. The cubic root of 166525661 is about 550.1659675436.

The spelling of 166525661 in words is "one hundred sixty-six million, five hundred twenty-five thousand, six hundred sixty-one".