31031021 has 8 divisors (see below), whose sum is σ = 35502720. Its totient is φ = 26569008.

The previous prime is 31031017. The next prime is 31031029. The reversal of 31031021 is 12013013.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31031021 - 2² = 31031017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31030993 and 31031011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31031029) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6800 + ... + 10406.

It is an arithmetic number, because the mean of its divisors is an integer number (4437840).

Almost surely, 2^31031021 is an apocalyptic number.

It is an amenable number.

31031021 is a deficient number, since it is larger than the sum of its proper divisors (4471699).

31031021 is a wasteful number, since it uses less digits than its factorization.

31031021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4843.

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

The square root of 31031021 is about 5570.5494343018. The cubic root of 31031021 is about 314.2428139298.

Adding to 31031021 its reverse (12013013), we get a palindrome (43044034).

The spelling of 31031021 in words is "thirty-one million, thirty-one thousand, twenty-one".