25631921 has 4 divisors (see below), whose sum is σ = 29293632. Its totient is φ = 21970212.

The previous prime is 25631891. The next prime is 25631927. The reversal of 25631921 is 12913652.

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 a cyclic number.

It is not a de Polignac number, because 25631921 - 2⁶ = 25631857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25631927) 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, 1830845 + ... + 1830858.

It is an arithmetic number, because the mean of its divisors is an integer number (7323408).

Almost surely, 2^25631921 is an apocalyptic number.

It is an amenable number.

25631921 is a deficient number, since it is larger than the sum of its proper divisors (3661711).

25631921 is an equidigital number, since it uses as much as digits as its factorization.

25631921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3661710.

The product of its digits is 3240, while the sum is 29.

The square root of 25631921 is about 5062.7977443307. The cubic root of 25631921 is about 294.8449668966.

The spelling of 25631921 in words is "twenty-five million, six hundred thirty-one thousand, nine hundred twenty-one".