31224209 has 2 divisors, whose sum is σ = 31224210. Its totient is φ = 31224208.

The previous prime is 31224199. The next prime is 31224229. The reversal of 31224209 is 90242213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25725184 + 5499025 = 5072^2 + 2345^2 .

It is an emirp because it is prime and its reverse (90242213) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31224209 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31224229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15612104 + 15612105.

It is an arithmetic number, because the mean of its divisors is an integer number (15612105).

Almost surely, 2^31224209 is an apocalyptic number.

It is an amenable number.

31224209 is a deficient number, since it is larger than the sum of its proper divisors (1).

31224209 is an equidigital number, since it uses as much as digits as its factorization.

31224209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 31224209 is about 5587.8626504237. The cubic root of 31224209 is about 314.8935862943.

The spelling of 31224209 in words is "thirty-one million, two hundred twenty-four thousand, two hundred nine".