81165803 has 4 divisors (see below), whose sum is σ = 85940280. Its totient is φ = 76391328.

The previous prime is 81165797. The next prime is 81165829. The reversal of 81165803 is 30856118.

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

It is a cyclic number.

It is not a de Polignac number, because 81165803 - 2⁸ = 81165547 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81165803.

It is not an unprimeable number, because it can be changed into a prime (81165863) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2387213 + ... + 2387246.

It is an arithmetic number, because the mean of its divisors is an integer number (21485070).

Almost surely, 2^81165803 is an apocalyptic number.

81165803 is a deficient number, since it is larger than the sum of its proper divisors (4774477).

81165803 is a wasteful number, since it uses less digits than its factorization.

81165803 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4774476.

The product of its (nonzero) digits is 5760, while the sum is 32.

The square root of 81165803 is about 9009.2065688383. The cubic root of 81165803 is about 432.9698912513.

The spelling of 81165803 in words is "eighty-one million, one hundred sixty-five thousand, eight hundred three".