25131209 has 2 divisors, whose sum is σ = 25131210. Its totient is φ = 25131208.

The previous prime is 25131193. The next prime is 25131217. The reversal of 25131209 is 90213152.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24403600 + 727609 = 4940^2 + 853^2 .

It is a cyclic number.

It is not a de Polignac number, because 25131209 - 2⁴ = 25131193 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (25131299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12565604 + 12565605.

It is an arithmetic number, because the mean of its divisors is an integer number (12565605).

Almost surely, 2^25131209 is an apocalyptic number.

It is an amenable number.

25131209 is a deficient number, since it is larger than the sum of its proper divisors (1).

25131209 is an equidigital number, since it uses as much as digits as its factorization.

25131209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 25131209 is about 5013.1037292280. The cubic root of 25131209 is about 292.9124247584.

The spelling of 25131209 in words is "twenty-five million, one hundred thirty-one thousand, two hundred nine".