165254345155421 has 4 divisors (see below), whose sum is σ = 165261327068700. Its totient is φ = 165247363242144.

The previous prime is 165254345155391. The next prime is 165254345155453. The reversal of 165254345155421 is 124551543452561.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 129959886000025 + 35294459155396 = 11399995^2 + 5940914^2 .

It is a cyclic number.

It is not a de Polignac number, because 165254345155421 - 2³⁰ = 165253271413597 is a prime.

It is a super-2 number, since 2×165254345155421² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165254345155481) 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, 3490921136 + ... + 3490968473.

It is an arithmetic number, because the mean of its divisors is an integer number (41315331767175).

Almost surely, 2^{165254345155421} is an apocalyptic number.

It is an amenable number.

165254345155421 is a deficient number, since it is larger than the sum of its proper divisors (6981913279).

165254345155421 is an equidigital number, since it uses as much as digits as its factorization.

165254345155421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6981913278.

The product of its digits is 14400000, while the sum is 53.

The spelling of 165254345155421 in words is "one hundred sixty-five trillion, two hundred fifty-four billion, three hundred forty-five million, one hundred fifty-five thousand, four hundred twenty-one".