81850999 has 2 divisors, whose sum is σ = 81851000. Its totient is φ = 81850998.

The previous prime is 81850991. The next prime is 81851083. The reversal of 81850999 is 99905818.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81850999 - 2³ = 81850991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81850991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40925499 + 40925500.

It is an arithmetic number, because the mean of its divisors is an integer number (40925500).

Almost surely, 2^81850999 is an apocalyptic number.

81850999 is a deficient number, since it is larger than the sum of its proper divisors (1).

81850999 is an equidigital number, since it uses as much as digits as its factorization.

81850999 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 233280, while the sum is 49.

The square root of 81850999 is about 9047.1541934467. The cubic root of 81850999 is about 434.1848459069.

The spelling of 81850999 in words is "eighty-one million, eight hundred fifty thousand, nine hundred ninety-nine".