21231021311 has 4 divisors (see below), whose sum is σ = 21244571712. Its totient is φ = 21217470912.

The previous prime is 21231021281. The next prime is 21231021337. The reversal of 21231021311 is 11312013212.

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 21231021311 - 2²⁶ = 21163912447 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 21231021311.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231021011) 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, 6772850 + ... + 6775983.

It is an arithmetic number, because the mean of its divisors is an integer number (5311142928).

Almost surely, 2^21231021311 is an apocalyptic number.

21231021311 is a deficient number, since it is larger than the sum of its proper divisors (13550401).

21231021311 is a wasteful number, since it uses less digits than its factorization.

21231021311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13550400.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21231021311 its reverse (11312013212), we get a palindrome (32543034523).

The spelling of 21231021311 in words is "twenty-one billion, two hundred thirty-one million, twenty-one thousand, three hundred eleven".