21311231231 has 8 divisors (see below), whose sum is σ = 22813094400. Its totient is φ = 19847390040.

The previous prime is 21311231219. The next prime is 21311231237. The reversal of 21311231231 is 13213211312.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21311231231 - 2⁶ = 21311231167 is a prime.

It is a super-2 number, since 2×21311231231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311231237) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9504335 + ... + 9506576.

It is an arithmetic number, because the mean of its divisors is an integer number (2851636800).

Almost surely, 2^21311231231 is an apocalyptic number.

21311231231 is a deficient number, since it is larger than the sum of its proper divisors (1501863169).

21311231231 is a wasteful number, since it uses less digits than its factorization.

21311231231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19010989.

The product of its digits is 216, while the sum is 20.

Adding to 21311231231 its reverse (13213211312), we get a palindrome (34524442543).

The spelling of 21311231231 in words is "twenty-one billion, three hundred eleven million, two hundred thirty-one thousand, two hundred thirty-one".