81639536335 has 16 divisors (see below), whose sum is σ = 114988815936. Its totient is φ = 54468384768.

The previous prime is 81639536287. The next prime is 81639536359. The reversal of 81639536335 is 53363593618.

It is not a de Polignac number, because 81639536335 - 2¹³ = 81639528143 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31519762 + ... + 31522351.

It is an arithmetic number, because the mean of its divisors is an integer number (7186800996).

Almost surely, 2^81639536335 is an apocalyptic number.

81639536335 is a deficient number, since it is larger than the sum of its proper divisors (33349279601).

81639536335 is a wasteful number, since it uses less digits than its factorization.

81639536335 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63042162.

The product of its digits is 5248800, while the sum is 52.

The spelling of 81639536335 in words is "eighty-one billion, six hundred thirty-nine million, five hundred thirty-six thousand, three hundred thirty-five".