81733865 has 4 divisors (see below), whose sum is σ = 98080644. Its totient is φ = 65387088.

The previous prime is 81733843. The next prime is 81733891. The reversal of 81733865 is 56833718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56833718 = 2 ⋅28416859.

It can be written as a sum of positive squares in 2 ways, for example, as 47499664 + 34234201 = 6892^2 + 5851^2 .

It is a cyclic number.

It is not a de Polignac number, because 81733865 - 2⁸ = 81733609 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8173382 + ... + 8173391.

It is an arithmetic number, because the mean of its divisors is an integer number (24520161).

Almost surely, 2^81733865 is an apocalyptic number.

It is an amenable number.

81733865 is a deficient number, since it is larger than the sum of its proper divisors (16346779).

81733865 is a wasteful number, since it uses less digits than its factorization.

81733865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16346778.

The product of its digits is 120960, while the sum is 41.

The square root of 81733865 is about 9040.6783484427. The cubic root of 81733865 is about 433.9776316276.

The spelling of 81733865 in words is "eighty-one million, seven hundred thirty-three thousand, eight hundred sixty-five".