166497981 has 8 divisors (see below), whose sum is σ = 239074080. Its totient is φ = 102460272.

The previous prime is 166497977. The next prime is 166498009. The reversal of 166497981 is 189794661.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 166497981 - 2² = 166497977 is a prime.

It is a super-2 number, since 2×166497981² = 55443155354152722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166497971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2134551 + ... + 2134628.

It is an arithmetic number, because the mean of its divisors is an integer number (29884260).

Almost surely, 2^166497981 is an apocalyptic number.

It is an amenable number.

166497981 is a deficient number, since it is larger than the sum of its proper divisors (72576099).

166497981 is a wasteful number, since it uses less digits than its factorization.

166497981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4269195.

The product of its digits is 653184, while the sum is 51.

The square root of 166497981 is about 12903.4096656659. The cubic root of 166497981 is about 550.1354828769.

The spelling of 166497981 in words is "one hundred sixty-six million, four hundred ninety-seven thousand, nine hundred eighty-one".