31013021 has 6 divisors (see below), whose sum is σ = 33582330. Its totient is φ = 28627248.

The previous prime is 31012973. The next prime is 31013023. The reversal of 31013021 is 12031013.

It can be written as a sum of positive squares in 3 ways, for example, as 1473796 + 29539225 = 1214^2 + 5435^2 .

It is a de Polignac number, because none of the positive numbers 2^k-31013021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 31012993 and 31013011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31013023) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 91586 + ... + 91923.

It is an arithmetic number, because the mean of its divisors is an integer number (5597055).

Almost surely, 2^31013021 is an apocalyptic number.

It is an amenable number.

31013021 is a deficient number, since it is larger than the sum of its proper divisors (2569309).

31013021 is a wasteful number, since it uses less digits than its factorization.

31013021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183535 (or 183522 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 11.

The square root of 31013021 is about 5568.9335603866. The cubic root of 31013021 is about 314.1820417895.

Adding to 31013021 its reverse (12031013), we get a palindrome (43044034).

It can be divided in two parts, 310 and 13021, that added together give a palindrome (13331).

The spelling of 31013021 in words is "thirty-one million, thirteen thousand, twenty-one".