31031213 has 4 divisors (see below), whose sum is σ = 31079388. Its totient is φ = 30983040.

The previous prime is 31031201. The next prime is 31031257. The reversal of 31031213 is 31213013.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18164644 + 12866569 = 4262^2 + 3587^2 .

It is a cyclic number.

It is not a de Polignac number, because 31031213 - 2¹⁰ = 31030189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31030213) 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, 23108 + ... + 24413.

It is an arithmetic number, because the mean of its divisors is an integer number (7769847).

Almost surely, 2^31031213 is an apocalyptic number.

It is an amenable number.

31031213 is a deficient number, since it is larger than the sum of its proper divisors (48175).

31031213 is an equidigital number, since it uses as much as digits as its factorization.

31031213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48174.

The product of its (nonzero) digits is 54, while the sum is 14.

The square root of 31031213 is about 5570.5666677637. The cubic root of 31031213 is about 314.2434620393.

Adding to 31031213 its reverse (31213013), we get a palindrome (62244226).

The spelling of 31031213 in words is "thirty-one million, thirty-one thousand, two hundred thirteen".