31303213 has 4 divisors (see below), whose sum is σ = 32066748. Its totient is φ = 30539680.

The previous prime is 31303193. The next prime is 31303229. The reversal of 31303213 is 31230313.

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 13972644 + 17330569 = 3738^2 + 4163^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31303213 is a prime.

It is a super-2 number, since 2×31303213² = 1959782288246738, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31303313) 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, 381706 + ... + 381787.

It is an arithmetic number, because the mean of its divisors is an integer number (8016687).

Almost surely, 2^31303213 is an apocalyptic number.

It is an amenable number.

31303213 is a deficient number, since it is larger than the sum of its proper divisors (763535).

31303213 is an equidigital number, since it uses as much as digits as its factorization.

31303213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 763534.

The product of its (nonzero) digits is 162, while the sum is 16.

The square root of 31303213 is about 5594.9274347394. The cubic root of 31303213 is about 315.1589455675.

Adding to 31303213 its reverse (31230313), we get a palindrome (62533526).

Subtracting from 31303213 its reverse (31230313), we obtain a square (72900 = 270²).

The spelling of 31303213 in words is "thirty-one million, three hundred three thousand, two hundred thirteen".