165254654265221 has 4 divisors (see below), whose sum is σ = 165254700726444. Its totient is φ = 165254607804000.

The previous prime is 165254654265209. The next prime is 165254654265257. The reversal of 165254654265221 is 122562456452561.

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 143748350040100 + 21506304225121 = 11989510^2 + 4637489^2 .

It is a cyclic number.

It is not a de Polignac number, because 165254654265221 - 2⁶ = 165254654265157 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 (165254654265121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17409080 + ... + 25171121.

It is an arithmetic number, because the mean of its divisors is an integer number (41313675181611).

Almost surely, 2^{165254654265221} is an apocalyptic number.

It is an amenable number.

165254654265221 is a deficient number, since it is larger than the sum of its proper divisors (46461223).

165254654265221 is an equidigital number, since it uses as much as digits as its factorization.

165254654265221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46461222.

The product of its digits is 34560000, while the sum is 56.

The spelling of 165254654265221 in words is "one hundred sixty-five trillion, two hundred fifty-four billion, six hundred fifty-four million, two hundred sixty-five thousand, two hundred twenty-one".