165566997 has 10 divisors (see below), whose sum is σ = 247328598. Its totient is φ = 110377944.

The previous prime is 165566981. The next prime is 165567037. The reversal of 165566997 is 799665561.

It can be written as a sum of positive squares in only one way, i.e., 102697956 + 62869041 = 10134^2 + 7929^2 .

It is not a de Polignac number, because 165566997 - 2⁴ = 165566981 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165566497) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1021938 + ... + 1022099.

Almost surely, 2^165566997 is an apocalyptic number.

It is an amenable number.

165566997 is a deficient number, since it is larger than the sum of its proper divisors (81761601).

165566997 is an equidigital number, since it uses as much as digits as its factorization.

165566997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2044049 (or 2044040 counting only the distinct ones).

The product of its digits is 3061800, while the sum is 54.

The square root of 165566997 is about 12867.2839791465. The cubic root of 165566997 is about 549.1081933142.

The spelling of 165566997 in words is "one hundred sixty-five million, five hundred sixty-six thousand, nine hundred ninety-seven".