81339199 has 2 divisors, whose sum is σ = 81339200. Its totient is φ = 81339198.

The previous prime is 81339191. The next prime is 81339217. The reversal of 81339199 is 99193318.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81339199 - 2³ = 81339191 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81339191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40669599 + 40669600.

It is an arithmetic number, because the mean of its divisors is an integer number (40669600).

Almost surely, 2^81339199 is an apocalyptic number.

81339199 is a deficient number, since it is larger than the sum of its proper divisors (1).

81339199 is an equidigital number, since it uses as much as digits as its factorization.

81339199 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 52488, while the sum is 43.

The square root of 81339199 is about 9018.8247017003. The cubic root of 81339199 is about 433.2779924725.

The spelling of 81339199 in words is "eighty-one million, three hundred thirty-nine thousand, one hundred ninety-nine".