2221855187165 has 4 divisors (see below), whose sum is σ = 2666226224604. Its totient is φ = 1777484149728.

The previous prime is 2221855187159. The next prime is 2221855187177. The reversal of 2221855187165 is 5617815581222.

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 1164096418489 + 1057758768676 = 1078933^2 + 1028474^2 .

It is a cyclic number.

It is not a de Polignac number, because 2221855187165 - 2⁸ = 2221855186909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 222185518712 + ... + 222185518721.

It is an arithmetic number, because the mean of its divisors is an integer number (666556556151).

Almost surely, 2^{2221855187165} is an apocalyptic number.

It is an amenable number.

2221855187165 is a deficient number, since it is larger than the sum of its proper divisors (444371037439).

2221855187165 is an equidigital number, since it uses as much as digits as its factorization.

2221855187165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 444371037438.

The product of its digits is 2688000, while the sum is 53.

The spelling of 2221855187165 in words is "two trillion, two hundred twenty-one billion, eight hundred fifty-five million, one hundred eighty-seven thousand, one hundred sixty-five".