165515531 has 2 divisors, whose sum is σ = 165515532. Its totient is φ = 165515530.

The previous prime is 165515503. The next prime is 165515561. The reversal of 165515531 is 135515561.

165515531 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is an emirp because it is prime and its reverse (135515561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 165515531 - 2¹⁰ = 165514507 is a prime.

It is a super-2 number, since 2×165515531² = 54790782004423922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (165515561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82757765 + 82757766.

It is an arithmetic number, because the mean of its divisors is an integer number (82757766).

Almost surely, 2^165515531 is an apocalyptic number.

165515531 is a deficient number, since it is larger than the sum of its proper divisors (1).

165515531 is an equidigital number, since it uses as much as digits as its factorization.

165515531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11250, while the sum is 32.

The square root of 165515531 is about 12865.2839455645. The cubic root of 165515531 is about 549.0512912111.

The spelling of 165515531 in words is "one hundred sixty-five million, five hundred fifteen thousand, five hundred thirty-one".