165456421 has 8 divisors (see below), whose sum is σ = 178314584. Its totient is φ = 152616960.

The previous prime is 165456413. The next prime is 165456449. The reversal of 165456421 is 124654561.

165456421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 7049025 + 158407396 = 2655^2 + 12586^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 165456421 - 2³ = 165456413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165456721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17701 + ... + 25381.

It is an arithmetic number, because the mean of its divisors is an integer number (22289323).

Almost surely, 2^165456421 is an apocalyptic number.

It is an amenable number.

165456421 is a deficient number, since it is larger than the sum of its proper divisors (12858163).

165456421 is a wasteful number, since it uses less digits than its factorization.

165456421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9351.

The product of its digits is 28800, while the sum is 34.

The square root of 165456421 is about 12862.9864728219. The cubic root of 165456421 is about 548.9859231540.

The spelling of 165456421 in words is "one hundred sixty-five million, four hundred fifty-six thousand, four hundred twenty-one".