166731689 has 4 divisors (see below), whose sum is σ = 166757520. Its totient is φ = 166705860.

The previous prime is 166731679. The next prime is 166731703. The reversal of 166731689 is 986137661.

It is a happy number.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 986137661 = 239 ⋅4126099.

It is a cyclic number.

It is not a de Polignac number, because 166731689 - 2¹² = 166727593 is a prime.

It is a super-2 number, since 2×166731689² = 55598912233585442, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (166731619) 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, 6074 + ... + 19244.

It is an arithmetic number, because the mean of its divisors is an integer number (41689380).

Almost surely, 2^166731689 is an apocalyptic number.

It is an amenable number.

166731689 is a deficient number, since it is larger than the sum of its proper divisors (25831).

166731689 is a wasteful number, since it uses less digits than its factorization.

166731689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25830.

The product of its digits is 326592, while the sum is 47.

The square root of 166731689 is about 12912.4625459283. The cubic root of 166731689 is about 550.3927651824.

The spelling of 166731689 in words is "one hundred sixty-six million, seven hundred thirty-one thousand, six hundred eighty-nine".