81838849 has 2 divisors, whose sum is σ = 81838850. Its totient is φ = 81838848.

The previous prime is 81838817. The next prime is 81838879. The reversal of 81838849 is 94883818.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55130625 + 26708224 = 7425^2 + 5168^2 .

It is a cyclic number.

It is not a de Polignac number, because 81838849 - 2⁵ = 81838817 is a prime.

It is not a weakly prime, because it can be changed into another prime (81838879) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40919424 + 40919425.

It is an arithmetic number, because the mean of its divisors is an integer number (40919425).

Almost surely, 2^81838849 is an apocalyptic number.

It is an amenable number.

81838849 is a deficient number, since it is larger than the sum of its proper divisors (1).

81838849 is an equidigital number, since it uses as much as digits as its factorization.

81838849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 442368, while the sum is 49.

The square root of 81838849 is about 9046.4826866578. The cubic root of 81838849 is about 434.1633613110.

The spelling of 81838849 in words is "eighty-one million, eight hundred thirty-eight thousand, eight hundred forty-nine".