81446839 has 2 divisors, whose sum is σ = 81446840. Its totient is φ = 81446838.

The previous prime is 81446831. The next prime is 81446861. The reversal of 81446839 is 93864418.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81446839 - 2³ = 81446831 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81446795 and 81446804.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81446831) 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, 40723419 + 40723420.

It is an arithmetic number, because the mean of its divisors is an integer number (40723420).

Almost surely, 2^81446839 is an apocalyptic number.

81446839 is a deficient number, since it is larger than the sum of its proper divisors (1).

81446839 is an equidigital number, since it uses as much as digits as its factorization.

81446839 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 165888, while the sum is 43.

The square root of 81446839 is about 9024.7902468700. The cubic root of 81446839 is about 433.4690339630.

The spelling of 81446839 in words is "eighty-one million, four hundred forty-six thousand, eight hundred thirty-nine".