81986437866 has 16 divisors (see below), whose sum is σ = 167066704224. Its totient is φ = 26813174544.

The previous prime is 81986437861. The next prime is 81986437877. The reversal of 81986437866 is 66873468918.

It is a super-3 number, since 3×81986437866³ (a number of 34 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81986437797 and 81986437806.

It is not an unprimeable number, because it can be changed into a prime (81986437861) 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, 128909176 + ... + 128909811.

It is an arithmetic number, because the mean of its divisors is an integer number (10441669014).

Almost surely, 2^81986437866 is an apocalyptic number.

81986437866 is an abundant number, since it is smaller than the sum of its proper divisors (85080266358).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81986437866 is a wasteful number, since it uses less digits than its factorization.

81986437866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257819045.

The product of its digits is 83607552, while the sum is 66.

The spelling of 81986437866 in words is "eighty-one billion, nine hundred eighty-six million, four hundred thirty-seven thousand, eight hundred sixty-six".