72781636387887 has 48 divisors (see below), whose sum is σ = 120510095427072. Its totient is φ = 41464012605120.

The previous prime is 72781636387877. The next prime is 72781636387969. The reversal of 72781636387887 is 78878363618727.

72781636387887 is a `hidden beast` number, since 7 + 2 + 78 + 163 + 6 + 387 + 8 + 8 + 7 = 666.

It is not a de Polignac number, because 72781636387887 - 2¹¹ = 72781636385839 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72781636387847) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 163232062 + ... + 163677332.

It is an arithmetic number, because the mean of its divisors is an integer number (2510626988064).

Almost surely, 2^{72781636387887} is an apocalyptic number.

72781636387887 is a deficient number, since it is larger than the sum of its proper divisors (47728459039185).

72781636387887 is a wasteful number, since it uses less digits than its factorization.

72781636387887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 453108 (or 453105 counting only the distinct ones).

The product of its digits is 6372753408, while the sum is 81.

The spelling of 72781636387887 in words is "seventy-two trillion, seven hundred eighty-one billion, six hundred thirty-six million, three hundred eighty-seven thousand, eight hundred eighty-seven".