81855113 has 2 divisors, whose sum is σ = 81855114. Its totient is φ = 81855112.

The previous prime is 81855079. The next prime is 81855121. The reversal of 81855113 is 31155818.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81234169 + 620944 = 9013^2 + 788^2 .

It is a cyclic number.

It is not a de Polignac number, because 81855113 - 2¹⁸ = 81592969 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81855113.

It is not a weakly prime, because it can be changed into another prime (81855013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40927556 + 40927557.

It is an arithmetic number, because the mean of its divisors is an integer number (40927557).

Almost surely, 2^81855113 is an apocalyptic number.

It is an amenable number.

81855113 is a deficient number, since it is larger than the sum of its proper divisors (1).

81855113 is an equidigital number, since it uses as much as digits as its factorization.

81855113 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4800, while the sum is 32.

The square root of 81855113 is about 9047.3815549031. The cubic root of 81855113 is about 434.1921201270.

The spelling of 81855113 in words is "eighty-one million, eight hundred fifty-five thousand, one hundred thirteen".