21131021313 has 8 divisors (see below), whose sum is σ = 31305216800. Its totient is φ = 14087347524.

The previous prime is 21131021297. The next prime is 21131021321. The reversal of 21131021313 is 31312013112.

21131021313 is a `hidden beast` number, since 21 + 1 + 310 + 21 + 313 = 666.

It is not a de Polignac number, because 21131021313 - 2⁴ = 21131021297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21131021713) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 391315183 + ... + 391315236.

It is an arithmetic number, because the mean of its divisors is an integer number (3913152100).

Almost surely, 2^21131021313 is an apocalyptic number.

It is an amenable number.

21131021313 is a deficient number, since it is larger than the sum of its proper divisors (10174195487).

21131021313 is an equidigital number, since it uses as much as digits as its factorization.

21131021313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 782630428 (or 782630422 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

Adding to 21131021313 its reverse (31312013112), we get a palindrome (52443034425).

The spelling of 21131021313 in words is "twenty-one billion, one hundred thirty-one million, twenty-one thousand, three hundred thirteen".