81244879 has 2 divisors, whose sum is σ = 81244880. Its totient is φ = 81244878.

The previous prime is 81244861. The next prime is 81244883. The reversal of 81244879 is 97844218.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81244879 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81244279) 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, 40622439 + 40622440.

It is an arithmetic number, because the mean of its divisors is an integer number (40622440).

Almost surely, 2^81244879 is an apocalyptic number.

81244879 is a deficient number, since it is larger than the sum of its proper divisors (1).

81244879 is an equidigital number, since it uses as much as digits as its factorization.

81244879 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 129024, while the sum is 43.

The square root of 81244879 is about 9013.5941222134. The cubic root of 81244879 is about 433.1104529706.

The spelling of 81244879 in words is "eighty-one million, two hundred forty-four thousand, eight hundred seventy-nine".