21320131021 has 16 divisors (see below), whose sum is σ = 25676035200. Its totient is φ = 17293851648.

The previous prime is 21320131013. The next prime is 21320131039. The reversal of 21320131021 is 12013102312.

It is a cyclic number.

It is not a de Polignac number, because 21320131021 - 2³ = 21320131013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21320130986 and 21320131004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21320131121) 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, 37281 + ... + 209833.

It is an arithmetic number, because the mean of its divisors is an integer number (1604752200).

Almost surely, 2^21320131021 is an apocalyptic number.

It is an amenable number.

21320131021 is a deficient number, since it is larger than the sum of its proper divisors (4355904179).

21320131021 is a wasteful number, since it uses less digits than its factorization.

21320131021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173508.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21320131021 its reverse (12013102312), we get a palindrome (33333233333).

The spelling of 21320131021 in words is "twenty-one billion, three hundred twenty million, one hundred thirty-one thousand, twenty-one".