31405205231 has 2 divisors, whose sum is σ = 31405205232. Its totient is φ = 31405205230.

The previous prime is 31405205189. The next prime is 31405205233. The reversal of 31405205231 is 13250250413.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31405205231 is a prime.

It is a super-2 number, since 2×31405205231² (a number of 22 digits) contains 22 as substring.

Together with 31405205233, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31405205231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31405205233) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15702602615 + 15702602616.

It is an arithmetic number, because the mean of its divisors is an integer number (15702602616).

Almost surely, 2^31405205231 is an apocalyptic number.

31405205231 is a deficient number, since it is larger than the sum of its proper divisors (1).

31405205231 is an equidigital number, since it uses as much as digits as its factorization.

31405205231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3600, while the sum is 26.

Adding to 31405205231 its reverse (13250250413), we get a palindrome (44655455644).

The spelling of 31405205231 in words is "thirty-one billion, four hundred five million, two hundred five thousand, two hundred thirty-one".