81813883 has 2 divisors, whose sum is σ = 81813884. Its totient is φ = 81813882.

The previous prime is 81813881. The next prime is 81813899. The reversal of 81813883 is 38831818.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81813883 - 2¹ = 81813881 is a prime.

It is a super-2 number, since 2×81813883² = 13387022903075378, which contains 22 as substring.

Together with 81813881, it forms a pair of twin primes.

It is equal to p_4769167 and since 81813883 and 4769167 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (81813881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40906941 + 40906942.

It is an arithmetic number, because the mean of its divisors is an integer number (40906942).

Almost surely, 2^81813883 is an apocalyptic number.

81813883 is a deficient number, since it is larger than the sum of its proper divisors (1).

81813883 is an equidigital number, since it uses as much as digits as its factorization.

81813883 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36864, while the sum is 40.

The square root of 81813883 is about 9045.1027080957. The cubic root of 81813883 is about 434.1192077701.

The spelling of 81813883 in words is "eighty-one million, eight hundred thirteen thousand, eight hundred eighty-three".