81017675728 has 120 divisors (see below), whose sum is σ = 174768758528. Its totient is φ = 36352800000.

The previous prime is 81017675719. The next prime is 81017675731. The reversal of 81017675728 is 82757671018.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 107879353 + ... + 107880103.

Almost surely, 2^81017675728 is an apocalyptic number.

81017675728 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81017675728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (87384379264).

81017675728 is an abundant number, since it is smaller than the sum of its proper divisors (93751082800).

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

81017675728 is a wasteful number, since it uses less digits than its factorization.

81017675728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1425 (or 1408 counting only the distinct ones).

The product of its (nonzero) digits is 1317120, while the sum is 52.

The spelling of 81017675728 in words is "eighty-one billion, seventeen million, six hundred seventy-five thousand, seven hundred twenty-eight".