81241187837 has 2 divisors, whose sum is σ = 81241187838. Its totient is φ = 81241187836.

The previous prime is 81241187831. The next prime is 81241187869. The reversal of 81241187837 is 73878114218.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 73989984121 + 7251203716 = 272011^2 + 85154^2 .

It is a cyclic number.

It is not a de Polignac number, because 81241187837 - 2⁶ = 81241187773 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81241187831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40620593918 + 40620593919.

It is an arithmetic number, because the mean of its divisors is an integer number (40620593919).

Almost surely, 2^81241187837 is an apocalyptic number.

It is an amenable number.

81241187837 is a deficient number, since it is larger than the sum of its proper divisors (1).

81241187837 is an equidigital number, since it uses as much as digits as its factorization.

81241187837 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 602112, while the sum is 50.

The spelling of 81241187837 in words is "eighty-one billion, two hundred forty-one million, one hundred eighty-seven thousand, eight hundred thirty-seven".