81259443987 has 8 divisors (see below), whose sum is σ = 108349878720. Its totient is φ = 54170985960.

The previous prime is 81259443971. The next prime is 81259444009. The reversal of 81259443987 is 78934495218.

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

It is not a de Polignac number, because 81259443987 - 2⁴ = 81259443971 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81259443987.

It is not an unprimeable number, because it can be changed into a prime (81259443917) 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, 395437 + ... + 564702.

It is an arithmetic number, because the mean of its divisors is an integer number (13543734840).

Almost surely, 2^81259443987 is an apocalyptic number.

81259443987 is a deficient number, since it is larger than the sum of its proper divisors (27090434733).

81259443987 is a wasteful number, since it uses less digits than its factorization.

81259443987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 988353.

The product of its digits is 17418240, while the sum is 60.

The spelling of 81259443987 in words is "eighty-one billion, two hundred fifty-nine million, four hundred forty-three thousand, nine hundred eighty-seven".