21321212313 has 16 divisors (see below), whose sum is σ = 29668101120. Its totient is φ = 13594391184.

The previous prime is 21321212309. The next prime is 21321212327. The reversal of 21321212313 is 31321212312.

It is not a de Polignac number, because 21321212313 - 2² = 21321212309 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21321212313.

It is not an unprimeable number, because it can be changed into a prime (21321212513) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 721258 + ... + 750236.

It is an arithmetic number, because the mean of its divisors is an integer number (1854256320).

Almost surely, 2^21321212313 is an apocalyptic number.

21321212313 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21321212313 is a deficient number, since it is larger than the sum of its proper divisors (8346888807).

21321212313 is a wasteful number, since it uses less digits than its factorization.

21321212313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39668.

The product of its digits is 432, while the sum is 21.

Adding to 21321212313 its reverse (31321212312), we get a palindrome (52642424625).

Subtracting 21321212313 from its reverse (31321212312), we obtain a palindrome (9999999999).

The spelling of 21321212313 in words is "twenty-one billion, three hundred twenty-one million, two hundred twelve thousand, three hundred thirteen".