81051187728 has 60 divisors (see below), whose sum is σ = 243567096720. Its totient is φ = 23157481536.

The previous prime is 81051187727. The next prime is 81051187843. The reversal of 81051187728 is 82778115018.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (81051187727) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17227918 + ... + 17232621.

It is an arithmetic number, because the mean of its divisors is an integer number (4059451612).

Almost surely, 2^81051187728 is an apocalyptic number.

It is an amenable number.

81051187728 is an abundant number, since it is smaller than the sum of its proper divisors (162515908992).

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

81051187728 is a wasteful number, since it uses less digits than its factorization.

81051187728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34460564 (or 34460551 counting only the distinct ones).

The product of its (nonzero) digits is 250880, while the sum is 48.

The spelling of 81051187728 in words is "eighty-one billion, fifty-one million, one hundred eighty-seven thousand, seven hundred twenty-eight".