25131809 has 2 divisors, whose sum is σ = 25131810. Its totient is φ = 25131808.

The previous prime is 25131791. The next prime is 25131853. The reversal of 25131809 is 90813152.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23493409 + 1638400 = 4847^2 + 1280^2 .

It is a cyclic number.

It is not a de Polignac number, because 25131809 - 2¹⁶ = 25066273 is a prime.

It is a super-2 number, since 2×25131809² = 1263215647224962, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (25131859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12565904 + 12565905.

It is an arithmetic number, because the mean of its divisors is an integer number (12565905).

Almost surely, 2^25131809 is an apocalyptic number.

It is an amenable number.

25131809 is a deficient number, since it is larger than the sum of its proper divisors (1).

25131809 is an equidigital number, since it uses as much as digits as its factorization.

25131809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 25131809 is about 5013.1635720371. The cubic root of 25131809 is about 292.9147558050.

The spelling of 25131809 in words is "twenty-five million, one hundred thirty-one thousand, eight hundred nine".