25810121 has 2 divisors, whose sum is σ = 25810122. Its totient is φ = 25810120.

The previous prime is 25810093. The next prime is 25810123. The reversal of 25810121 is 12101852.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25806400 + 3721 = 5080^2 + 61^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25810121 is a prime.

It is a Sophie Germain prime.

Together with 25810123, it forms a pair of twin primes.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 25810093 and 25810102.

It is not a weakly prime, because it can be changed into another prime (25810123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12905060 + 12905061.

It is an arithmetic number, because the mean of its divisors is an integer number (12905061).

Almost surely, 2^25810121 is an apocalyptic number.

It is an amenable number.

25810121 is a deficient number, since it is larger than the sum of its proper divisors (1).

25810121 is an equidigital number, since it uses as much as digits as its factorization.

25810121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 160, while the sum is 20.

The square root of 25810121 is about 5080.3662269565. The cubic root of 25810121 is about 295.5266700047.

Adding to 25810121 its reverse (12101852), we get a palindrome (37911973).

The spelling of 25810121 in words is "twenty-five million, eight hundred ten thousand, one hundred twenty-one".