25817861 has 2 divisors, whose sum is σ = 25817862. Its totient is φ = 25817860.

The previous prime is 25817851. The next prime is 25817867. The reversal of 25817861 is 16871852.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25300900 + 516961 = 5030^2 + 719^2 .

It is a cyclic number.

It is not a de Polignac number, because 25817861 - 2⁶ = 25817797 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25817867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12908930 + 12908931.

It is an arithmetic number, because the mean of its divisors is an integer number (12908931).

Almost surely, 2^25817861 is an apocalyptic number.

It is an amenable number.

25817861 is a deficient number, since it is larger than the sum of its proper divisors (1).

25817861 is an equidigital number, since it uses as much as digits as its factorization.

25817861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26880, while the sum is 38.

The square root of 25817861 is about 5081.1279259629. The cubic root of 25817861 is about 295.5562081306.

The spelling of 25817861 in words is "twenty-five million, eight hundred seventeen thousand, eight hundred sixty-one".