81593236078 has 4 divisors (see below), whose sum is σ = 122389854120. Its totient is φ = 40796618038.

The previous prime is 81593236003. The next prime is 81593236103. The reversal of 81593236078 is 87063239518.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87063239518 = 2 ⋅43531619759.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20398309018 + ... + 20398309021.

It is an arithmetic number, because the mean of its divisors is an integer number (30597463530).

Almost surely, 2^81593236078 is an apocalyptic number.

81593236078 is a deficient number, since it is larger than the sum of its proper divisors (40796618042).

81593236078 is a wasteful number, since it uses less digits than its factorization.

81593236078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40796618041.

The product of its (nonzero) digits is 2177280, while the sum is 52.

The spelling of 81593236078 in words is "eighty-one billion, five hundred ninety-three million, two hundred thirty-six thousand, seventy-eight".