165043331136521 has 4 divisors (see below), whose sum is σ = 165045745142544. Its totient is φ = 165040917130500.

The previous prime is 165043331136469. The next prime is 165043331136571. The reversal of 165043331136521 is 125631133340561.

165043331136521 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 Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 165043331136521 - 2⁴² = 160645284625417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165043331136571) 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, 1206900455 + ... + 1207037196.

It is an arithmetic number, because the mean of its divisors is an integer number (41261436285636).

Almost surely, 2^{165043331136521} is an apocalyptic number.

It is an amenable number.

165043331136521 is a deficient number, since it is larger than the sum of its proper divisors (2414006023).

165043331136521 is an equidigital number, since it uses as much as digits as its factorization.

165043331136521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2414006022.

The product of its (nonzero) digits is 583200, while the sum is 44.

The spelling of 165043331136521 in words is "one hundred sixty-five trillion, forty-three billion, three hundred thirty-one million, one hundred thirty-six thousand, five hundred twenty-one".