25844191861 has 2 divisors, whose sum is σ = 25844191862. Its totient is φ = 25844191860.

The previous prime is 25844191847. The next prime is 25844191871. The reversal of 25844191861 is 16819144852.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17846288100 + 7997903761 = 133590^2 + 89431^2 .

It is a cyclic number.

It is not a de Polignac number, because 25844191861 - 2⁵ = 25844191829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25844191801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12922095930 + 12922095931.

It is an arithmetic number, because the mean of its divisors is an integer number (12922095931).

Almost surely, 2^25844191861 is an apocalyptic number.

It is an amenable number.

25844191861 is a deficient number, since it is larger than the sum of its proper divisors (1).

25844191861 is an equidigital number, since it uses as much as digits as its factorization.

25844191861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 552960, while the sum is 49.

The spelling of 25844191861 in words is "twenty-five billion, eight hundred forty-four million, one hundred ninety-one thousand, eight hundred sixty-one".