81838265 has 16 divisors (see below), whose sum is σ = 101287632. Its totient is φ = 63431424.

The previous prime is 81838247. The next prime is 81838277. The reversal of 81838265 is 56283818.

It can be written as a sum of positive squares in 8 ways, for example, as 2699449 + 79138816 = 1643^2 + 8896^2 .

It is a cyclic number.

It is not a de Polignac number, because 81838265 - 2¹⁶ = 81772729 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 50447 + ... + 52043.

It is an arithmetic number, because the mean of its divisors is an integer number (6330477).

Almost surely, 2^81838265 is an apocalyptic number.

It is an amenable number.

81838265 is a deficient number, since it is larger than the sum of its proper divisors (19449367).

81838265 is a wasteful number, since it uses less digits than its factorization.

81838265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1916.

The product of its digits is 92160, while the sum is 41.

The square root of 81838265 is about 9046.4504088620. The cubic root of 81838265 is about 434.1623285822.

The spelling of 81838265 in words is "eighty-one million, eight hundred thirty-eight thousand, two hundred sixty-five".