31304431 has 4 divisors (see below), whose sum is σ = 31343112. Its totient is φ = 31265752.

The previous prime is 31304423. The next prime is 31304437. The reversal of 31304431 is 13440313.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13440313 = 61 ⋅220333.

It is a cyclic number.

It is not a de Polignac number, because 31304431 - 2³ = 31304423 is a prime.

It is a super-2 number, since 2×31304431² = 1959934800467522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31304399 and 31304408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31304437) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18100 + ... + 19753.

It is an arithmetic number, because the mean of its divisors is an integer number (7835778).

Almost surely, 2^31304431 is an apocalyptic number.

31304431 is a deficient number, since it is larger than the sum of its proper divisors (38681).

31304431 is an equidigital number, since it uses as much as digits as its factorization.

31304431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38680.

The product of its (nonzero) digits is 432, while the sum is 19.

The square root of 31304431 is about 5595.0362822774. The cubic root of 31304431 is about 315.1630330991.

Adding to 31304431 its reverse (13440313), we get a palindrome (44744744).

The spelling of 31304431 in words is "thirty-one million, three hundred four thousand, four hundred thirty-one".