165220405 has 24 divisors (see below), whose sum is σ = 236012832. Its totient is φ = 110652192.

The previous prime is 165220403. The next prime is 165220411. The reversal of 165220405 is 504022561.

It is not a de Polignac number, because 165220405 - 2¹ = 165220403 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 165220405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165220403) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2694 + ... + 18376.

It is an arithmetic number, because the mean of its divisors is an integer number (9833868).

Almost surely, 2^165220405 is an apocalyptic number.

It is an amenable number.

165220405 is a deficient number, since it is larger than the sum of its proper divisors (70792427).

165220405 is a wasteful number, since it uses less digits than its factorization.

165220405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15745 (or 15738 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 165220405 is about 12853.8089685509. The cubic root of 165220405 is about 548.7247645198.

Adding to 165220405 its reverse (504022561), we get a palindrome (669242966).

The spelling of 165220405 in words is "one hundred sixty-five million, two hundred twenty thousand, four hundred five".