165220989 has 4 divisors (see below), whose sum is σ = 220294656. Its totient is φ = 110147324.

The previous prime is 165220907. The next prime is 165220997. The reversal of 165220989 is 989022561.

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.

It is a cyclic number.

It is not a de Polignac number, because 165220989 - 2¹² = 165216893 is a prime.

It is a super-2 number, since 2×165220989² = 54595950412276242, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 165220989.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165220189) 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, 27536829 + ... + 27536834.

It is an arithmetic number, because the mean of its divisors is an integer number (55073664).

Almost surely, 2^165220989 is an apocalyptic number.

It is an amenable number.

165220989 is a deficient number, since it is larger than the sum of its proper divisors (55073667).

165220989 is an equidigital number, since it uses as much as digits as its factorization.

165220989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55073666.

The product of its (nonzero) digits is 77760, while the sum is 42.

The square root of 165220989 is about 12853.8316855325. The cubic root of 165220989 is about 548.7254110398.

The spelling of 165220989 in words is "one hundred sixty-five million, two hundred twenty thousand, nine hundred eighty-nine".