165402401 has 4 divisors (see below), whose sum is σ = 175131972. Its totient is φ = 155672832.

The previous prime is 165402389. The next prime is 165402403. The reversal of 165402401 is 104204561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 104204561 = 59 ⋅1766179.

It can be written as a sum of positive squares in 2 ways, for example, as 127148176 + 38254225 = 11276^2 + 6185^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165402401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165402403) 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, 4864760 + ... + 4864793.

It is an arithmetic number, because the mean of its divisors is an integer number (43782993).

Almost surely, 2^165402401 is an apocalyptic number.

It is an amenable number.

165402401 is a deficient number, since it is larger than the sum of its proper divisors (9729571).

165402401 is an equidigital number, since it uses as much as digits as its factorization.

165402401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9729570.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 165402401 is about 12860.8864779999. The cubic root of 165402401 is about 548.9261703654.

Adding to 165402401 its reverse (104204561), we get a palindrome (269606962).

The spelling of 165402401 in words is "one hundred sixty-five million, four hundred two thousand, four hundred one".