21421037111 has 4 divisors (see below), whose sum is σ = 21426368424. Its totient is φ = 21415705800.

The previous prime is 21421037101. The next prime is 21421037147. The reversal of 21421037111 is 11173012412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21421037111 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421037101) 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, 2659625 + ... + 2667666.

It is an arithmetic number, because the mean of its divisors is an integer number (5356592106).

Almost surely, 2^21421037111 is an apocalyptic number.

21421037111 is a deficient number, since it is larger than the sum of its proper divisors (5331313).

21421037111 is an equidigital number, since it uses as much as digits as its factorization.

21421037111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5331312.

The product of its (nonzero) digits is 336, while the sum is 23.

Adding to 21421037111 its reverse (11173012412), we get a palindrome (32594049523).

The spelling of 21421037111 in words is "twenty-one billion, four hundred twenty-one million, thirty-seven thousand, one hundred eleven".