81477756904872 has 32 divisors (see below), whose sum is σ = 205043361756480. Its totient is φ = 26979389702400.

The previous prime is 81477756904793. The next prime is 81477756904897. The reversal of 81477756904872 is 27840965777418.

It is a junction number, because it is equal to n+sod(n) for n = 81477756904794 and 81477756904803.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11241408753 + ... + 11241416000.

It is an arithmetic number, because the mean of its divisors is an integer number (6407605054890).

Almost surely, 2^{81477756904872} is an apocalyptic number.

It is an amenable number.

81477756904872 is an abundant number, since it is smaller than the sum of its proper divisors (123565604851608).

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

81477756904872 is a wasteful number, since it uses less digits than its factorization.

81477756904872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22482824913 (or 22482824909 counting only the distinct ones).

The product of its (nonzero) digits is 1327656960, while the sum is 75.

The spelling of 81477756904872 in words is "eighty-one trillion, four hundred seventy-seven billion, seven hundred fifty-six million, nine hundred four thousand, eight hundred seventy-two".