25491909 has 4 divisors (see below), whose sum is σ = 33989216. Its totient is φ = 16994604.

The previous prime is 25491883. The next prime is 25491913. The reversal of 25491909 is 90919452.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 25491909 - 2⁵ = 25491877 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25491989) 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 in 3 ways as a sum of consecutive naturals, for example, 4248649 + ... + 4248654.

It is an arithmetic number, because the mean of its divisors is an integer number (8497304).

Almost surely, 2^25491909 is an apocalyptic number.

It is an amenable number.

25491909 is a deficient number, since it is larger than the sum of its proper divisors (8497307).

25491909 is an equidigital number, since it uses as much as digits as its factorization.

25491909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8497306.

The product of its (nonzero) digits is 29160, while the sum is 39.

The square root of 25491909 is about 5048.9512772456. The cubic root of 25491909 is about 294.3071319510.

The spelling of 25491909 in words is "twenty-five million, four hundred ninety-one thousand, nine hundred nine".