165252421 has 4 divisors (see below), whose sum is σ = 165278412. Its totient is φ = 165226432.

The previous prime is 165252389. The next prime is 165252467. The reversal of 165252421 is 124252561.

165252421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 146676321 + 18576100 = 12111^2 + 4310^2 .

It is a cyclic number.

It is not a de Polignac number, because 165252421 - 2⁵ = 165252389 is a prime.

It is a super-2 number, since 2×165252421² = 54616725292722482, which contains 22 as substring.

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 165252421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165252491) 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, 3645 + ... + 18541.

It is an arithmetic number, because the mean of its divisors is an integer number (41319603).

Almost surely, 2^165252421 is an apocalyptic number.

It is an amenable number.

165252421 is a deficient number, since it is larger than the sum of its proper divisors (25991).

165252421 is a wasteful number, since it uses less digits than its factorization.

165252421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25990.

The product of its digits is 4800, while the sum is 28.

The square root of 165252421 is about 12855.0542978239. The cubic root of 165252421 is about 548.7602057383.

The spelling of 165252421 in words is "one hundred sixty-five million, two hundred fifty-two thousand, four hundred twenty-one".