81199099 has 2 divisors, whose sum is σ = 81199100. Its totient is φ = 81199098.

The previous prime is 81199091. The next prime is 81199133. The reversal of 81199099 is 99099118.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81199099 - 2³ = 81199091 is a prime.

It is not a weakly prime, because it can be changed into another prime (81199091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40599549 + 40599550.

It is an arithmetic number, because the mean of its divisors is an integer number (40599550).

Almost surely, 2^81199099 is an apocalyptic number.

81199099 is a deficient number, since it is larger than the sum of its proper divisors (1).

81199099 is an equidigital number, since it uses as much as digits as its factorization.

81199099 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 52488, while the sum is 46.

The square root of 81199099 is about 9011.0542668436. The cubic root of 81199099 is about 433.0290877525.

The spelling of 81199099 in words is "eighty-one million, one hundred ninety-nine thousand, ninety-nine".