25258721 has 4 divisors (see below), whose sum is σ = 25282452. Its totient is φ = 25234992.

The previous prime is 25258711. The next prime is 25258757. The reversal of 25258721 is 12785252.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 5107600 + 20151121 = 2260^2 + 4489^2 .

It is a cyclic number.

It is not a de Polignac number, because 25258721 - 2¹⁸ = 24996577 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (25258711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10190 + ... + 12423.

It is an arithmetic number, because the mean of its divisors is an integer number (6320613).

Almost surely, 2^25258721 is an apocalyptic number.

It is an amenable number.

25258721 is a deficient number, since it is larger than the sum of its proper divisors (23731).

25258721 is a wasteful number, since it uses less digits than its factorization.

25258721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23730.

The product of its digits is 11200, while the sum is 32.

The square root of 25258721 is about 5025.8055075779. The cubic root of 25258721 is about 293.4069872150.

The spelling of 25258721 in words is "twenty-five million, two hundred fifty-eight thousand, seven hundred twenty-one".