165258494021 has 4 divisors (see below), whose sum is σ = 165438319200. Its totient is φ = 165078668844.

The previous prime is 165258494003. The next prime is 165258494047. The reversal of 165258494021 is 120494852561.

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 a de Polignac number, because none of the positive numbers 2^k-165258494021 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 (165258494081) 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, 89911211 + ... + 89913048.

It is an arithmetic number, because the mean of its divisors is an integer number (41359579800).

Almost surely, 2^165258494021 is an apocalyptic number.

It is an amenable number.

165258494021 is a deficient number, since it is larger than the sum of its proper divisors (179825179).

165258494021 is an equidigital number, since it uses as much as digits as its factorization.

165258494021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179825178.

The product of its (nonzero) digits is 691200, while the sum is 47.

The spelling of 165258494021 in words is "one hundred sixty-five billion, two hundred fifty-eight million, four hundred ninety-four thousand, twenty-one".