21231131231 has 8 divisors (see below), whose sum is σ = 21945212928. Its totient is φ = 20518875000.

The previous prime is 21231131227. The next prime is 21231131237. The reversal of 21231131231 is 13213113212.

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 21231131231 - 2² = 21231131227 is a prime.

It is a super-2 number, since 2×21231131231² (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 (21231131237) 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, 432695 + ... + 479256.

It is an arithmetic number, because the mean of its divisors is an integer number (2743151616).

Almost surely, 2^21231131231 is an apocalyptic number.

21231131231 is a deficient number, since it is larger than the sum of its proper divisors (714081697).

21231131231 is an equidigital number, since it uses as much as digits as its factorization.

21231131231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 912733.

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

Adding to 21231131231 its reverse (13213113212), we get a palindrome (34444244443).

The spelling of 21231131231 in words is "twenty-one billion, two hundred thirty-one million, one hundred thirty-one thousand, two hundred thirty-one".