25821121 has 4 divisors (see below), whose sum is σ = 25831872. Its totient is φ = 25810372.

The previous prime is 25821101. The next prime is 25821127. The reversal of 25821121 is 12112852.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 25821121 - 2¹⁵ = 25788353 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 25821092 and 25821101.

It is not an unprimeable number, because it can be changed into a prime (25821127) 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, 60 + ... + 7186.

It is an arithmetic number, because the mean of its divisors is an integer number (6457968).

Almost surely, 2^25821121 is an apocalyptic number.

It is an amenable number.

25821121 is a deficient number, since it is larger than the sum of its proper divisors (10751).

25821121 is an equidigital number, since it uses as much as digits as its factorization.

25821121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10750.

The product of its digits is 320, while the sum is 22.

The square root of 25821121 is about 5081.4487107517. The cubic root of 25821121 is about 295.5686474866.

Adding to 25821121 its reverse (12112852), we get a palindrome (37933973).

The spelling of 25821121 in words is "twenty-five million, eight hundred twenty-one thousand, one hundred twenty-one".