21213312313 has 4 divisors (see below), whose sum is σ = 21214462500. Its totient is φ = 21212162128.

The previous prime is 21213312271. The next prime is 21213312319. The reversal of 21213312313 is 31321331212.

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 9906818089 + 11306494224 = 99533^2 + 106332^2 .

It is a cyclic number.

It is not a de Polignac number, because 21213312313 - 2²¹ = 21211215161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21213312319) 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, 546970 + ... + 584467.

It is an arithmetic number, because the mean of its divisors is an integer number (5303615625).

Almost surely, 2^21213312313 is an apocalyptic number.

It is an amenable number.

21213312313 is a deficient number, since it is larger than the sum of its proper divisors (1150187).

21213312313 is a wasteful number, since it uses less digits than its factorization.

21213312313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1150186.

The product of its digits is 648, while the sum is 22.

Adding to 21213312313 its reverse (31321331212), we get a palindrome (52534643525).

The spelling of 21213312313 in words is "twenty-one billion, two hundred thirteen million, three hundred twelve thousand, three hundred thirteen".