25731921 has 4 divisors (see below), whose sum is σ = 34309232. Its totient is φ = 17154612.

The previous prime is 25731911. The next prime is 25731949. The reversal of 25731921 is 12913752.

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 25731921 - 2¹⁴ = 25715537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25731911) 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, 4288651 + ... + 4288656.

It is an arithmetic number, because the mean of its divisors is an integer number (8577308).

Almost surely, 2^25731921 is an apocalyptic number.

It is an amenable number.

25731921 is a deficient number, since it is larger than the sum of its proper divisors (8577311).

25731921 is an equidigital number, since it uses as much as digits as its factorization.

25731921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8577310.

The product of its digits is 3780, while the sum is 30.

The square root of 25731921 is about 5072.6640929594. The cubic root of 25731921 is about 295.2279039398.

The spelling of 25731921 in words is "twenty-five million, seven hundred thirty-one thousand, nine hundred twenty-one".