25639491 has 4 divisors (see below), whose sum is σ = 34185992. Its totient is φ = 17092992.

The previous prime is 25639489. The next prime is 25639501. The reversal of 25639491 is 19493652.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 25639491 - 2¹ = 25639489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25639441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4273246 + ... + 4273251.

It is an arithmetic number, because the mean of its divisors is an integer number (8546498).

Almost surely, 2^25639491 is an apocalyptic number.

25639491 is a deficient number, since it is larger than the sum of its proper divisors (8546501).

25639491 is an equidigital number, since it uses as much as digits as its factorization.

25639491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8546500.

The product of its digits is 58320, while the sum is 39.

The square root of 25639491 is about 5063.5452994913. The cubic root of 25639491 is about 294.8739900393.

The spelling of 25639491 in words is "twenty-five million, six hundred thirty-nine thousand, four hundred ninety-one".