81865354 has 4 divisors (see below), whose sum is σ = 122798034. Its totient is φ = 40932676.

The previous prime is 81865351. The next prime is 81865361. The reversal of 81865354 is 45356818.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 77845329 + 4020025 = 8823^2 + 2005^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (81865351) 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, 20466337 + ... + 20466340.

Almost surely, 2^81865354 is an apocalyptic number.

81865354 is a deficient number, since it is larger than the sum of its proper divisors (40932680).

81865354 is a wasteful number, since it uses less digits than its factorization.

81865354 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40932679.

The product of its digits is 115200, while the sum is 40.

The square root of 81865354 is about 9047.9475020581. The cubic root of 81865354 is about 434.2102268194.

The spelling of 81865354 in words is "eighty-one million, eight hundred sixty-five thousand, three hundred fifty-four".