21222015515555 has 4 divisors (see below), whose sum is σ = 25466418618672. Its totient is φ = 16977612412440.

The previous prime is 21222015515537. The next prime is 21222015515593. The reversal of 21222015515555 is 55551551022212.

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

It is not a de Polignac number, because 21222015515555 - 2⁸ = 21222015515299 is a prime.

It is a Duffinian 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, 2122201551551 + ... + 2122201551560.

It is an arithmetic number, because the mean of its divisors is an integer number (6366604654668).

Almost surely, 2^{21222015515555} is an apocalyptic number.

21222015515555 is a deficient number, since it is larger than the sum of its proper divisors (4244403103117).

21222015515555 is an equidigital number, since it uses as much as digits as its factorization.

21222015515555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4244403103116.

The product of its (nonzero) digits is 250000, while the sum is 41.

Adding to 21222015515555 its reverse (55551551022212), we get a palindrome (76773566537767).

The spelling of 21222015515555 in words is "twenty-one trillion, two hundred twenty-two billion, fifteen million, five hundred fifteen thousand, five hundred fifty-five".