25994721 has 4 divisors (see below), whose sum is σ = 34659632. Its totient is φ = 17329812.

The previous prime is 25994711. The next prime is 25994753. The reversal of 25994721 is 12749952.

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 25994721 - 2¹⁹ = 25470433 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 25994721.

It is not an unprimeable number, because it can be changed into a prime (25994711) 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, 4332451 + ... + 4332456.

It is an arithmetic number, because the mean of its divisors is an integer number (8664908).

Almost surely, 2^25994721 is an apocalyptic number.

It is an amenable number.

25994721 is a deficient number, since it is larger than the sum of its proper divisors (8664911).

25994721 is an equidigital number, since it uses as much as digits as its factorization.

25994721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8664910.

The product of its digits is 45360, while the sum is 39.

The square root of 25994721 is about 5098.5018387758. The cubic root of 25994721 is about 296.2295554621.

The spelling of 25994721 in words is "twenty-five million, nine hundred ninety-four thousand, seven hundred twenty-one".