25121891 has 2 divisors, whose sum is σ = 25121892. Its totient is φ = 25121890.

The previous prime is 25121881. The next prime is 25121893. The reversal of 25121891 is 19812152.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 25121891 - 2¹⁰ = 25120867 is a prime.

It is a super-2 number, since 2×25121891² = 1262218814831762, which contains 22 as substring.

Together with 25121893, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (25121893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12560945 + 12560946.

It is an arithmetic number, because the mean of its divisors is an integer number (12560946).

Almost surely, 2^25121891 is an apocalyptic number.

25121891 is a deficient number, since it is larger than the sum of its proper divisors (1).

25121891 is an equidigital number, since it uses as much as digits as its factorization.

25121891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 29.

The square root of 25121891 is about 5012.1742786938. The cubic root of 25121891 is about 292.8762188418.

The spelling of 25121891 in words is "twenty-five million, one hundred twenty-one thousand, eight hundred ninety-one".