81003657120 has 192 divisors, whose sum is σ = 256779694080. Its totient is φ = 21464499200.

The previous prime is 81003657101. The next prime is 81003657127. The reversal of 81003657120 is 2175630018.

It is not an unprimeable number, because it can be changed into a prime (81003657127) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 64339051 + ... + 64340309.

It is an arithmetic number, because the mean of its divisors is an integer number (1337394240).

Almost surely, 2^81003657120 is an apocalyptic number.

81003657120 is a gapful number since it is divisible by the number (80) 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 81003657120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128389847040).

81003657120 is an abundant number, since it is smaller than the sum of its proper divisors (175776036960).

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

81003657120 is a wasteful number, since it uses less digits than its factorization.

81003657120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2019 (or 2011 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 33.

The spelling of 81003657120 in words is "eighty-one billion, three million, six hundred fifty-seven thousand, one hundred twenty".