81865371 has 8 divisors (see below), whose sum is σ = 124747264. Its totient is φ = 46780200.

The previous prime is 81865369. The next prime is 81865373. The reversal of 81865371 is 17356818.

It is an interprime number because it is at equal distance from previous prime (81865369) and next prime (81865373).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81865371 - 2¹ = 81865369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81865373) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1949155 + ... + 1949196.

It is an arithmetic number, because the mean of its divisors is an integer number (15593408).

Almost surely, 2^81865371 is an apocalyptic number.

81865371 is a deficient number, since it is larger than the sum of its proper divisors (42881893).

81865371 is a wasteful number, since it uses less digits than its factorization.

81865371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3898361.

The product of its digits is 40320, while the sum is 39.

The square root of 81865371 is about 9047.9484414977. The cubic root of 81865371 is about 434.2102568752.

The spelling of 81865371 in words is "eighty-one million, eight hundred sixty-five thousand, three hundred seventy-one".