21111111013 has 4 divisors (see below), whose sum is σ = 21114475200. Its totient is φ = 21107746828.

The previous prime is 21111110981. The next prime is 21111111023. The reversal of 21111111013 is 31011111112.

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 21111111013 - 2⁵ = 21111110981 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111110984 and 21111111002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111111023) 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, 1672663 + ... + 1685236.

It is an arithmetic number, because the mean of its divisors is an integer number (5278618800).

Almost surely, 2^21111111013 is an apocalyptic number.

It is an amenable number.

21111111013 is a deficient number, since it is larger than the sum of its proper divisors (3364187).

21111111013 is an equidigital number, since it uses as much as digits as its factorization.

21111111013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3364186.

The product of its (nonzero) digits is 6, while the sum is 13.

Adding to 21111111013 its reverse (31011111112), we get a palindrome (52122222125).

Subtracting 21111111013 from its reverse (31011111112), we obtain a palindrome (9900000099).

The spelling of 21111111013 in words is "twenty-one billion, one hundred eleven million, one hundred eleven thousand, thirteen".