81855337 has 2 divisors, whose sum is σ = 81855338. Its totient is φ = 81855336.

The previous prime is 81855329. The next prime is 81855377. The reversal of 81855337 is 73355818.

It is an a-pointer prime, because the next prime (81855377) can be obtained adding 81855337 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54700816 + 27154521 = 7396^2 + 5211^2 .

It is a cyclic number.

It is not a de Polignac number, because 81855337 - 2³ = 81855329 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 81855337.

It is not a weakly prime, because it can be changed into another prime (81855317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40927668 + 40927669.

It is an arithmetic number, because the mean of its divisors is an integer number (40927669).

Almost surely, 2^81855337 is an apocalyptic number.

It is an amenable number.

81855337 is a deficient number, since it is larger than the sum of its proper divisors (1).

81855337 is an equidigital number, since it uses as much as digits as its factorization.

81855337 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 100800, while the sum is 40.

The square root of 81855337 is about 9047.3939341669. The cubic root of 81855337 is about 434.1925161883.

The spelling of 81855337 in words is "eighty-one million, eight hundred fifty-five thousand, three hundred thirty-seven".