81940859377 has 8 divisors (see below), whose sum is σ = 90628975976. Its totient is φ = 73593453312.

The previous prime is 81940859353. The next prime is 81940859387. The reversal of 81940859377 is 77395804918.

It can be written as a sum of positive squares in 4 ways, for example, as 37527825841 + 44413033536 = 193721^2 + 210744^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81940859377 - 2¹¹ = 81940857329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81940859387) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85177128 + ... + 85178089.

It is an arithmetic number, because the mean of its divisors is an integer number (11328621997).

Almost surely, 2^81940859377 is an apocalyptic number.

It is an amenable number.

81940859377 is a deficient number, since it is larger than the sum of its proper divisors (8688116599).

81940859377 is a wasteful number, since it uses less digits than its factorization.

81940859377 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170355267.

The product of its (nonzero) digits is 15240960, while the sum is 61.

The spelling of 81940859377 in words is "eighty-one billion, nine hundred forty million, eight hundred fifty-nine thousand, three hundred seventy-seven".