25765981 has 2 divisors, whose sum is σ = 25765982. Its totient is φ = 25765980.

The previous prime is 25765979. The next prime is 25766017. The reversal of 25765981 is 18956752.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23677956 + 2088025 = 4866^2 + 1445^2 .

It is a cyclic number.

It is not a de Polignac number, because 25765981 - 2¹ = 25765979 is a prime.

It is a super-2 number, since 2×25765981² = 1327771553784722, which contains 22 as substring.

Together with 25765979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25765951) 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, 12882990 + 12882991.

It is an arithmetic number, because the mean of its divisors is an integer number (12882991).

Almost surely, 2^25765981 is an apocalyptic number.

It is an amenable number.

25765981 is a deficient number, since it is larger than the sum of its proper divisors (1).

25765981 is an equidigital number, since it uses as much as digits as its factorization.

25765981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 151200, while the sum is 43.

The square root of 25765981 is about 5076.0201930252. The cubic root of 25765981 is about 295.3581057624.

The spelling of 25765981 in words is "twenty-five million, seven hundred sixty-five thousand, nine hundred eighty-one".