21216612311215 has 8 divisors (see below), whose sum is σ = 25460408215008. Its totient is φ = 16972974221280.

The previous prime is 21216612311183. The next prime is 21216612311239. The reversal of 21216612311215 is 51211321661212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21216612311215 - 2⁵ = 21216612311183 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 39157491 + ... + 39695620.

It is an arithmetic number, because the mean of its divisors is an integer number (3182551026876).

Almost surely, 2^{21216612311215} is an apocalyptic number.

21216612311215 is a deficient number, since it is larger than the sum of its proper divisors (4243795903793).

21216612311215 is an equidigital number, since it uses as much as digits as its factorization.

21216612311215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78906929.

The product of its digits is 8640, while the sum is 34.

Adding to 21216612311215 its reverse (51211321661212), we get a palindrome (72427933972427).

The spelling of 21216612311215 in words is "twenty-one trillion, two hundred sixteen billion, six hundred twelve million, three hundred eleven thousand, two hundred fifteen".