81804199 has 2 divisors, whose sum is σ = 81804200. Its totient is φ = 81804198.

The previous prime is 81804193. The next prime is 81804211. The reversal of 81804199 is 99140818.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81804199 - 2²⁵ = 48249767 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81804193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40902099 + 40902100.

It is an arithmetic number, because the mean of its divisors is an integer number (40902100).

Almost surely, 2^81804199 is an apocalyptic number.

81804199 is a deficient number, since it is larger than the sum of its proper divisors (1).

81804199 is an equidigital number, since it uses as much as digits as its factorization.

81804199 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 40.

The square root of 81804199 is about 9044.5673749495. The cubic root of 81804199 is about 434.1020787445.

The spelling of 81804199 in words is "eighty-one million, eight hundred four thousand, one hundred ninety-nine".