21215133113 has 4 divisors (see below), whose sum is σ = 21263023248. Its totient is φ = 21167242980.

The previous prime is 21215133101. The next prime is 21215133157. The reversal of 21215133113 is 31133151212.

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 not a de Polignac number, because 21215133113 - 2²² = 21210938809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21215193113) 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, 23944403 + ... + 23945288.

It is an arithmetic number, because the mean of its divisors is an integer number (5315755812).

Almost surely, 2^21215133113 is an apocalyptic number.

It is an amenable number.

21215133113 is a deficient number, since it is larger than the sum of its proper divisors (47890135).

21215133113 is an equidigital number, since it uses as much as digits as its factorization.

21215133113 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47890134.

The product of its digits is 540, while the sum is 23.

Adding to 21215133113 its reverse (31133151212), we get a palindrome (52348284325).

The spelling of 21215133113 in words is "twenty-one billion, two hundred fifteen million, one hundred thirty-three thousand, one hundred thirteen".