31121313 has 4 divisors (see below), whose sum is σ = 41495088. Its totient is φ = 20747540.

The previous prime is 31121309. The next prime is 31121341. The reversal of 31121313 is 31312113.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 31121313 - 2² = 31121309 is a prime.

It is a super-2 number, since 2×31121313² = 1937072245687938, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31121292 and 31121301.

It is not an unprimeable number, because it can be changed into a prime (31121393) 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, 5186883 + ... + 5186888.

It is an arithmetic number, because the mean of its divisors is an integer number (10373772).

Almost surely, 2^31121313 is an apocalyptic number.

It is an amenable number.

31121313 is a deficient number, since it is larger than the sum of its proper divisors (10373775).

31121313 is a wasteful number, since it uses less digits than its factorization.

31121313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10373774.

The product of its digits is 54, while the sum is 15.

The square root of 31121313 is about 5578.6479544779. The cubic root of 31121313 is about 314.5473063996.

Adding to 31121313 its reverse (31312113), we get a palindrome (62433426).

The spelling of 31121313 in words is "thirty-one million, one hundred twenty-one thousand, three hundred thirteen".