81007388928 has 144 divisors (see below), whose sum is σ = 243614548800. Its totient is φ = 26544660480.

The previous prime is 81007388927. The next prime is 81007388933. The reversal of 81007388928 is 82988370018.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (81007388921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 308488 + ... + 507128.

It is an arithmetic number, because the mean of its divisors is an integer number (1691767700).

Almost surely, 2^81007388928 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81007388928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121807274400).

81007388928 is an abundant number, since it is smaller than the sum of its proper divisors (162607159872).

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

81007388928 is a wasteful number, since it uses less digits than its factorization.

81007388928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198725 (or 198705 counting only the distinct ones).

The product of its (nonzero) digits is 1548288, while the sum is 54.

The spelling of 81007388928 in words is "eighty-one billion, seven million, three hundred eighty-eight thousand, nine hundred twenty-eight".