31113021 has 4 divisors (see below), whose sum is σ = 41484032. Its totient is φ = 20742012.

The previous prime is 31113011. The next prime is 31113023. The reversal of 31113021 is 12031113.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12031113 = 3 ⋅4010371.

It is not a de Polignac number, because 31113021 - 2⁶ = 31112957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31112988 and 31113006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31113023) 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, 5185501 + ... + 5185506.

It is an arithmetic number, because the mean of its divisors is an integer number (10371008).

Almost surely, 2^31113021 is an apocalyptic number.

It is an amenable number.

31113021 is a deficient number, since it is larger than the sum of its proper divisors (10371011).

31113021 is a wasteful number, since it uses less digits than its factorization.

31113021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10371010.

The product of its (nonzero) digits is 18, while the sum is 12.

The square root of 31113021 is about 5577.9047141377. The cubic root of 31113021 is about 314.5193677975.

Adding to 31113021 its reverse (12031113), we get a palindrome (43144134).

The spelling of 31113021 in words is "thirty-one million, one hundred thirteen thousand, twenty-one".