81244861 has 2 divisors, whose sum is σ = 81244862. Its totient is φ = 81244860.

The previous prime is 81244781. The next prime is 81244879. The reversal of 81244861 is 16844218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60140025 + 21104836 = 7755^2 + 4594^2 .

It is a cyclic number.

It is not a de Polignac number, because 81244861 - 2⁷ = 81244733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81244061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40622430 + 40622431.

It is an arithmetic number, because the mean of its divisors is an integer number (40622431).

Almost surely, 2^81244861 is an apocalyptic number.

It is an amenable number.

81244861 is a deficient number, since it is larger than the sum of its proper divisors (1).

81244861 is an equidigital number, since it uses as much as digits as its factorization.

81244861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12288, while the sum is 34.

The square root of 81244861 is about 9013.5931237215. The cubic root of 81244861 is about 433.1104209851.

The spelling of 81244861 in words is "eighty-one million, two hundred forty-four thousand, eight hundred sixty-one".