25631621 has 8 divisors (see below), whose sum is σ = 26592600. Its totient is φ = 24675840.

The previous prime is 25631611. The next prime is 25631623. The reversal of 25631621 is 12613652.

It can be written as a sum of positive squares in 4 ways, for example, as 10962721 + 14668900 = 3311^2 + 3830^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 25631621 - 2¹⁰ = 25630597 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 (25631623) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10781 + ... + 12941.

It is an arithmetic number, because the mean of its divisors is an integer number (3324075).

Almost surely, 2^25631621 is an apocalyptic number.

It is an amenable number.

25631621 is a deficient number, since it is larger than the sum of its proper divisors (960979).

25631621 is a wasteful number, since it uses less digits than its factorization.

25631621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2599.

The product of its digits is 2160, while the sum is 26.

The square root of 25631621 is about 5062.7681163569. The cubic root of 25631621 is about 294.8438165882.

The spelling of 25631621 in words is "twenty-five million, six hundred thirty-one thousand, six hundred twenty-one".