81332239 has 2 divisors, whose sum is σ = 81332240. Its totient is φ = 81332238.

The previous prime is 81332201. The next prime is 81332257. The reversal of 81332239 is 93223318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81332239 - 2¹¹ = 81330191 is a prime.

It is a super-2 number, since 2×81332239² = 13229866201506242, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81332239.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81336239) 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, 40666119 + 40666120.

It is an arithmetic number, because the mean of its divisors is an integer number (40666120).

Almost surely, 2^81332239 is an apocalyptic number.

81332239 is a deficient number, since it is larger than the sum of its proper divisors (1).

81332239 is an equidigital number, since it uses as much as digits as its factorization.

81332239 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7776, while the sum is 31.

The square root of 81332239 is about 9018.4388338559. The cubic root of 81332239 is about 433.2656339341.

The spelling of 81332239 in words is "eighty-one million, three hundred thirty-two thousand, two hundred thirty-nine".