166632581 has 4 divisors (see below), whose sum is σ = 166663200. Its totient is φ = 166601964.

The previous prime is 166632563. The next prime is 166632593. The reversal of 166632581 is 185236661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 185236661 = 83 ⋅2231767.

It is a cyclic number.

It is not a de Polignac number, because 166632581 - 2¹⁰ = 166631557 is a prime.

It is a super-2 number, since 2×166632581² = 55532834101443122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166632481) 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, 4691 + ... + 18848.

It is an arithmetic number, because the mean of its divisors is an integer number (41665800).

Almost surely, 2^166632581 is an apocalyptic number.

It is an amenable number.

166632581 is a deficient number, since it is larger than the sum of its proper divisors (30619).

166632581 is an equidigital number, since it uses as much as digits as its factorization.

166632581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30618.

The product of its digits is 51840, while the sum is 38.

The square root of 166632581 is about 12908.6242876613. The cubic root of 166632581 is about 550.2836894608.

The spelling of 166632581 in words is "one hundred sixty-six million, six hundred thirty-two thousand, five hundred eighty-one".