8181371520 has 512 divisors, whose sum is σ = 33371136000. Its totient is φ = 1855623168.

The previous prime is 8181371501. The next prime is 8181371521. The reversal of 8181371520 is 251731818.

It is a super-2 number, since 2×8181371520² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (8181371521) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 28909299 + ... + 28909581.

It is an arithmetic number, because the mean of its divisors is an integer number (65178000).

Almost surely, 2^8181371520 is an apocalyptic number.

8181371520 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 8181371520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16685568000).

8181371520 is an abundant number, since it is smaller than the sum of its proper divisors (25189764480).

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

8181371520 is a wasteful number, since it uses less digits than its factorization.

8181371520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 557 (or 539 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 36.

The square root of 8181371520 is about 90450.9343235326. The cubic root of 8181371520 is about 2015.0014896536.

The spelling of 8181371520 in words is "eight billion, one hundred eighty-one million, three hundred seventy-one thousand, five hundred twenty".