21131100013 has 4 divisors (see below), whose sum is σ = 21131604928. Its totient is φ = 21130595100.

The previous prime is 21131099993. The next prime is 21131100019. The reversal of 21131100013 is 31000113112.

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 21131100013 - 2⁵ = 21131099981 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21131099966 and 21131100002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131100019) 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, 183381 + ... + 275482.

It is an arithmetic number, because the mean of its divisors is an integer number (5282901232).

Almost surely, 2^21131100013 is an apocalyptic number.

It is an amenable number.

21131100013 is a deficient number, since it is larger than the sum of its proper divisors (504915).

21131100013 is an equidigital number, since it uses as much as digits as its factorization.

21131100013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 504914.

The product of its (nonzero) digits is 18, while the sum is 13.

Adding to 21131100013 its reverse (31000113112), we get a palindrome (52131213125).

The spelling of 21131100013 in words is "twenty-one billion, one hundred thirty-one million, one hundred thousand, thirteen".