81439684335787 has 8 divisors (see below), whose sum is σ = 89011875100032. Its totient is φ = 74176562582400.

The previous prime is 81439684335733. The next prime is 81439684335791. The reversal of 81439684335787 is 78753348693418.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81439684335787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81439684335727) 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, 77267252164 + ... + 77267253217.

It is an arithmetic number, because the mean of its divisors is an integer number (11126484387504).

Almost surely, 2^{81439684335787} is an apocalyptic number.

81439684335787 is a deficient number, since it is larger than the sum of its proper divisors (7572190764245).

81439684335787 is a wasteful number, since it uses less digits than its factorization.

81439684335787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154534505429.

The product of its digits is 2926264320, while the sum is 76.

The spelling of 81439684335787 in words is "eighty-one trillion, four hundred thirty-nine billion, six hundred eighty-four million, three hundred thirty-five thousand, seven hundred eighty-seven".