31425209 has 2 divisors, whose sum is σ = 31425210. Its totient is φ = 31425208.

The previous prime is 31425193. The next prime is 31425223. The reversal of 31425209 is 90252413.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29735209 + 1690000 = 5453^2 + 1300^2 .

It is a cyclic number.

It is not a de Polignac number, because 31425209 - 2⁴ = 31425193 is a prime.

It is not a weakly prime, because it can be changed into another prime (31425509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15712604 + 15712605.

It is an arithmetic number, because the mean of its divisors is an integer number (15712605).

Almost surely, 2^31425209 is an apocalyptic number.

It is an amenable number.

31425209 is a deficient number, since it is larger than the sum of its proper divisors (1).

31425209 is an equidigital number, since it uses as much as digits as its factorization.

31425209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 31425209 is about 5605.8192086438. The cubic root of 31425209 is about 315.5678310860.

The spelling of 31425209 in words is "thirty-one million, four hundred twenty-five thousand, two hundred nine".