21201331231 has 2 divisors, whose sum is σ = 21201331232. Its totient is φ = 21201331230.

The previous prime is 21201331219. The next prime is 21201331259. The reversal of 21201331231 is 13213310212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21201331231 - 2²³ = 21192942623 is a prime.

It is a super-2 number, since 2×21201331231² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21201331199 and 21201331208.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201331211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600665615 + 10600665616.

It is an arithmetic number, because the mean of its divisors is an integer number (10600665616).

Almost surely, 2^21201331231 is an apocalyptic number.

21201331231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201331231 is an equidigital number, since it uses as much as digits as its factorization.

21201331231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21201331231 its reverse (13213310212), we get a palindrome (34414641443).

The spelling of 21201331231 in words is "twenty-one billion, two hundred one million, three hundred thirty-one thousand, two hundred thirty-one".