31323431 has 2 divisors, whose sum is σ = 31323432. Its totient is φ = 31323430.

The previous prime is 31323403. The next prime is 31323449. The reversal of 31323431 is 13432313.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31323431 is a prime.

It is a super-2 number, since 2×31323431² = 1962314659223522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31323491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15661715 + 15661716.

It is an arithmetic number, because the mean of its divisors is an integer number (15661716).

Almost surely, 2^31323431 is an apocalyptic number.

31323431 is a deficient number, since it is larger than the sum of its proper divisors (1).

31323431 is an equidigital number, since it uses as much as digits as its factorization.

31323431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 20.

The square root of 31323431 is about 5596.7339583010. The cubic root of 31323431 is about 315.2267821847.

Adding to 31323431 its reverse (13432313), we get a palindrome (44755744).

The spelling of 31323431 in words is "thirty-one million, three hundred twenty-three thousand, four hundred thirty-one".