21311321233 has 4 divisors (see below), whose sum is σ = 21479127040. Its totient is φ = 21143515428.

The previous prime is 21311321197. The next prime is 21311321237. The reversal of 21311321233 is 33212311312.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21311321233 is a prime.

It is a super-2 number, since 2×21311321233² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21311321237) 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, 83902713 + ... + 83902966.

It is an arithmetic number, because the mean of its divisors is an integer number (5369781760).

Almost surely, 2^21311321233 is an apocalyptic number.

It is an amenable number.

21311321233 is a deficient number, since it is larger than the sum of its proper divisors (167805807).

21311321233 is a wasteful number, since it uses less digits than its factorization.

21311321233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167805806.

The product of its digits is 648, while the sum is 22.

Adding to 21311321233 its reverse (33212311312), we get a palindrome (54523632545).

The spelling of 21311321233 in words is "twenty-one billion, three hundred eleven million, three hundred twenty-one thousand, two hundred thirty-three".