165987801 has 12 divisors (see below), whose sum is σ = 274011712. Its totient is φ = 94850136.

The previous prime is 165987763. The next prime is 165987817. The reversal of 165987801 is 108789561.

It is not a de Polignac number, because 165987801 - 2⁶ = 165987737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165987821) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1317301 + ... + 1317426.

Almost surely, 2^165987801 is an apocalyptic number.

It is an amenable number.

165987801 is a deficient number, since it is larger than the sum of its proper divisors (108023911).

165987801 is a wasteful number, since it uses less digits than its factorization.

165987801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2634740 (or 2634737 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 45.

The square root of 165987801 is about 12883.6253050141. The cubic root of 165987801 is about 549.5730030185.

The spelling of 165987801 in words is "one hundred sixty-five million, nine hundred eighty-seven thousand, eight hundred one".