21310211111 has 4 divisors (see below), whose sum is σ = 24354526992. Its totient is φ = 18265895232.

The previous prime is 21310211081. The next prime is 21310211123. The reversal of 21310211111 is 11111201312.

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

It is a cyclic number.

It is not a de Polignac number, because 21310211111 - 2¹⁸ = 21309948967 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 (21310211911) 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, 1522157930 + ... + 1522157943.

It is an arithmetic number, because the mean of its divisors is an integer number (6088631748).

Almost surely, 2^21310211111 is an apocalyptic number.

21310211111 is a deficient number, since it is larger than the sum of its proper divisors (3044315881).

21310211111 is an equidigital number, since it uses as much as digits as its factorization.

21310211111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3044315880.

The product of its (nonzero) digits is 12, while the sum is 14.

Adding to 21310211111 its reverse (11111201312), we get a palindrome (32421412423).

The spelling of 21310211111 in words is "twenty-one billion, three hundred ten million, two hundred eleven thousand, one hundred eleven".