21001111100913 has 4 divisors (see below), whose sum is σ = 28001481467888. Its totient is φ = 14000740733940.

The previous prime is 21001111100903. The next prime is 21001111100923. The reversal of 21001111100913 is 31900111110012.

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 an interprime number because it is at equal distance from previous prime (21001111100903) and next prime (21001111100923).

It is not a de Polignac number, because 21001111100913 - 2²⁸ = 21000842665457 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21001111100913.

It is not an unprimeable number, because it can be changed into a prime (21001111100903) 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, 3500185183483 + ... + 3500185183488.

It is an arithmetic number, because the mean of its divisors is an integer number (7000370366972).

Almost surely, 2^{21001111100913} is an apocalyptic number.

It is an amenable number.

21001111100913 is a deficient number, since it is larger than the sum of its proper divisors (7000370366975).

21001111100913 is an equidigital number, since it uses as much as digits as its factorization.

21001111100913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7000370366974.

The product of its (nonzero) digits is 54, while the sum is 21.

Adding to 21001111100913 its reverse (31900111110012), we get a palindrome (52901222210925).

The spelling of 21001111100913 in words is "twenty-one trillion, one billion, one hundred eleven million, one hundred thousand, nine hundred thirteen".