21311202111 has 4 divisors (see below), whose sum is σ = 28414936152. Its totient is φ = 14207468072.

The previous prime is 21311202103. The next prime is 21311202113. The reversal of 21311202111 is 11120211312.

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 21311202111 - 2³ = 21311202103 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311202113) 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, 3551867016 + ... + 3551867021.

It is an arithmetic number, because the mean of its divisors is an integer number (7103734038).

Almost surely, 2^21311202111 is an apocalyptic number.

21311202111 is a deficient number, since it is larger than the sum of its proper divisors (7103734041).

21311202111 is an equidigital number, since it uses as much as digits as its factorization.

21311202111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7103734040.

The product of its (nonzero) digits is 24, while the sum is 15.

Adding to 21311202111 its reverse (11120211312), we get a palindrome (32431413423).

The spelling of 21311202111 in words is "twenty-one billion, three hundred eleven million, two hundred two thousand, one hundred eleven".