81886125689 has 2 divisors, whose sum is σ = 81886125690. Its totient is φ = 81886125688.

The previous prime is 81886125583. The next prime is 81886125697. The reversal of 81886125689 is 98652168818.

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., 81633061225 + 253064464 = 285715^2 + 15908^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81886125689 is a prime.

It is not a weakly prime, because it can be changed into another prime (81886175689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40943062844 + 40943062845.

It is an arithmetic number, because the mean of its divisors is an integer number (40943062845).

Almost surely, 2^81886125689 is an apocalyptic number.

It is an amenable number.

81886125689 is a deficient number, since it is larger than the sum of its proper divisors (1).

81886125689 is an equidigital number, since it uses as much as digits as its factorization.

81886125689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13271040, while the sum is 62.

The spelling of 81886125689 in words is "eighty-one billion, eight hundred eighty-six million, one hundred twenty-five thousand, six hundred eighty-nine".