81940859378 has 16 divisors (see below), whose sum is σ = 141282014400. Its totient is φ = 34914518736.

The previous prime is 81940859353. The next prime is 81940859387. The reversal of 81940859378 is 87395804918.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81940859378.

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, 16913528 + ... + 16918371.

It is an arithmetic number, because the mean of its divisors is an integer number (8830125900).

Almost surely, 2^81940859378 is an apocalyptic number.

81940859378 is a deficient number, since it is larger than the sum of its proper divisors (59341155022).

81940859378 is a wasteful number, since it uses less digits than its factorization.

81940859378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33832081.

The product of its (nonzero) digits is 17418240, while the sum is 62.

The spelling of 81940859378 in words is "eighty-one billion, nine hundred forty million, eight hundred fifty-nine thousand, three hundred seventy-eight".