165565491 has 48 divisors (see below), whose sum is σ = 279869184. Its totient is φ = 84779136.

The previous prime is 165565489. The next prime is 165565493. The reversal of 165565491 is 194565561.

It is an interprime number because it is at equal distance from previous prime (165565489) and next prime (165565493).

It is not a de Polignac number, because 165565491 - 2¹ = 165565489 is a prime.

Its product of digits (162000) is a multiple of the sum of its prime factors (540).

It is not an unprimeable number, because it can be changed into a prime (165565493) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 373516 + ... + 373958.

It is an arithmetic number, because the mean of its divisors is an integer number (5830608).

Almost surely, 2^165565491 is an apocalyptic number.

165565491 is a deficient number, since it is larger than the sum of its proper divisors (114303693).

165565491 is a wasteful number, since it uses less digits than its factorization.

165565491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 540 (or 503 counting only the distinct ones).

The product of its digits is 162000, while the sum is 42.

The square root of 165565491 is about 12867.2254585050. The cubic root of 165565491 is about 549.1065284103.

The spelling of 165565491 in words is "one hundred sixty-five million, five hundred sixty-five thousand, four hundred ninety-one".