25457821 has 4 divisors (see below), whose sum is σ = 25481500. Its totient is φ = 25434144.

The previous prime is 25457819. The next prime is 25457867. The reversal of 25457821 is 12875452.

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 15288100 + 10169721 = 3910^2 + 3189^2 .

It is a cyclic number.

It is not a de Polignac number, because 25457821 - 2¹ = 25457819 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25457921) 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, 10146 + ... + 12403.

It is an arithmetic number, because the mean of its divisors is an integer number (6370375).

Almost surely, 2^25457821 is an apocalyptic number.

It is an amenable number.

25457821 is a deficient number, since it is larger than the sum of its proper divisors (23679).

25457821 is a wasteful number, since it uses less digits than its factorization.

25457821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23678.

The product of its digits is 22400, while the sum is 34.

The square root of 25457821 is about 5045.5743974299. The cubic root of 25457821 is about 294.1758900915.

The spelling of 25457821 in words is "twenty-five million, four hundred fifty-seven thousand, eight hundred twenty-one".