25921921 has 4 divisors (see below), whose sum is σ = 26758144. Its totient is φ = 25085700.

The previous prime is 25921919. The next prime is 25921967. The reversal of 25921921 is 12912952.

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 25921921 - 2¹ = 25921919 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 836191 = 25921921 / (2 + 5 + 9 + 2 + 1 + 9 + 2 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25921901) 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, 418065 + ... + 418126.

It is an arithmetic number, because the mean of its divisors is an integer number (6689536).

Almost surely, 2^25921921 is an apocalyptic number.

It is an amenable number.

25921921 is a deficient number, since it is larger than the sum of its proper divisors (836223).

25921921 is an equidigital number, since it uses as much as digits as its factorization.

25921921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 836222.

The product of its digits is 3240, while the sum is 31.

The square root of 25921921 is about 5091.3574810653. The cubic root of 25921921 is about 295.9527598400.

The spelling of 25921921 in words is "twenty-five million, nine hundred twenty-one thousand, nine hundred twenty-one".