81593823 has 4 divisors (see below), whose sum is σ = 108791768. Its totient is φ = 54395880.

The previous prime is 81593821. The next prime is 81593851. The reversal of 81593823 is 32839518.

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

It is not a de Polignac number, because 81593823 - 2¹ = 81593821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81593821) 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, 13598968 + ... + 13598973.

It is an arithmetic number, because the mean of its divisors is an integer number (27197942).

Almost surely, 2^81593823 is an apocalyptic number.

81593823 is a deficient number, since it is larger than the sum of its proper divisors (27197945).

81593823 is a wasteful number, since it uses less digits than its factorization.

81593823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27197944.

The product of its digits is 51840, while the sum is 39.

The square root of 81593823 is about 9032.9299233416. The cubic root of 81593823 is about 433.7296322659.

The spelling of 81593823 in words is "eighty-one million, five hundred ninety-three thousand, eight hundred twenty-three".