25643891 has 24 divisors (see below), whose sum is σ = 32412960. Its totient is φ = 19858176.

The previous prime is 25643879. The next prime is 25643897. The reversal of 25643891 is 19834652.

It is a happy number.

It is not a de Polignac number, because 25643891 - 2¹⁴ = 25627507 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25643897) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 62495 + ... + 62903.

It is an arithmetic number, because the mean of its divisors is an integer number (1350540).

Almost surely, 2^25643891 is an apocalyptic number.

25643891 is a deficient number, since it is larger than the sum of its proper divisors (6769069).

25643891 is a wasteful number, since it uses less digits than its factorization.

25643891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 495 (or 482 counting only the distinct ones).

The product of its digits is 51840, while the sum is 38.

The square root of 25643891 is about 5063.9797590433. The cubic root of 25643891 is about 294.8908568763.

The spelling of 25643891 in words is "twenty-five million, six hundred forty-three thousand, eight hundred ninety-one".