25891001 has 2 divisors, whose sum is σ = 25891002. Its totient is φ = 25891000.

The previous prime is 25890989. The next prime is 25891003. The reversal of 25891001 is 10019852.

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., 23863225 + 2027776 = 4885^2 + 1424^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25891001 is a prime.

Together with 25891003, 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 (25891003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12945500 + 12945501.

It is an arithmetic number, because the mean of its divisors is an integer number (12945501).

Almost surely, 2^25891001 is an apocalyptic number.

It is an amenable number.

25891001 is a deficient number, since it is larger than the sum of its proper divisors (1).

25891001 is an equidigital number, since it uses as much as digits as its factorization.

25891001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 25891001 is about 5088.3200567574. The cubic root of 25891001 is about 295.8350409388.

The spelling of 25891001 in words is "twenty-five million, eight hundred ninety-one thousand, one".