81396239 has 2 divisors, whose sum is σ = 81396240. Its totient is φ = 81396238.

The previous prime is 81396233. The next prime is 81396251. The reversal of 81396239 is 93269318.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81396239 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 81396196 and 81396205.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81396233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40698119 + 40698120.

It is an arithmetic number, because the mean of its divisors is an integer number (40698120).

Almost surely, 2^81396239 is an apocalyptic number.

81396239 is a deficient number, since it is larger than the sum of its proper divisors (1).

81396239 is an equidigital number, since it uses as much as digits as its factorization.

81396239 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69984, while the sum is 41.

The square root of 81396239 is about 9021.9864220691. The cubic root of 81396239 is about 433.3792491123.

The spelling of 81396239 in words is "eighty-one million, three hundred ninety-six thousand, two hundred thirty-nine".