81355793 has 4 divisors (see below), whose sum is σ = 81425520. Its totient is φ = 81286068.

The previous prime is 81355787. The next prime is 81355801. The reversal of 81355793 is 39755318.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81355793 - 2²⁰ = 80307217 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 81355793.

It is not an unprimeable number, because it can be changed into a prime (81355733) 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 in 3 ways as a sum of consecutive naturals, for example, 33083 + ... + 35456.

It is an arithmetic number, because the mean of its divisors is an integer number (20356380).

Almost surely, 2^81355793 is an apocalyptic number.

It is an amenable number.

81355793 is a deficient number, since it is larger than the sum of its proper divisors (69727).

81355793 is a wasteful number, since it uses less digits than its factorization.

81355793 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69726.

The product of its digits is 113400, while the sum is 41.

The square root of 81355793 is about 9019.7446194446. The cubic root of 81355793 is about 433.3074547991.

The spelling of 81355793 in words is "eighty-one million, three hundred fifty-five thousand, seven hundred ninety-three".