81285675156784 has 40 divisors (see below), whose sum is σ = 182455321749920. Its totient is φ = 34359502606848.

The previous prime is 81285675156773. The next prime is 81285675156817. The reversal of 81285675156784 is 48765157658218.

It is a Harshad number since it is a multiple of its sum of digits (73).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4970984679 + ... + 4971001030.

It is an arithmetic number, because the mean of its divisors is an integer number (4561383043748).

Almost surely, 2^{81285675156784} is an apocalyptic number.

It is an amenable number.

81285675156784 is an abundant number, since it is smaller than the sum of its proper divisors (101169646593136).

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

81285675156784 is a wasteful number, since it uses less digits than its factorization.

81285675156784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9941985797 (or 9941985791 counting only the distinct ones).

The product of its digits is 903168000, while the sum is 73.

The spelling of 81285675156784 in words is "eighty-one trillion, two hundred eighty-five billion, six hundred seventy-five million, one hundred fifty-six thousand, seven hundred eighty-four".