81593872378 has 16 divisors (see below), whose sum is σ = 128070347400. Its totient is φ = 38945365056.

The previous prime is 81593872313. The next prime is 81593872427. The reversal of 81593872378 is 87327839518.

It can be written as a sum of positive squares in 4 ways, for example, as 75813767649 + 5780104729 = 275343^2 + 76027^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10398153 + ... + 10405996.

Almost surely, 2^81593872378 is an apocalyptic number.

81593872378 is a deficient number, since it is larger than the sum of its proper divisors (46476475022).

81593872378 is a wasteful number, since it uses less digits than its factorization.

81593872378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20804241.

The product of its digits is 20321280, while the sum is 61.

The spelling of 81593872378 in words is "eighty-one billion, five hundred ninety-three million, eight hundred seventy-two thousand, three hundred seventy-eight".