81338560 has 56 divisors (see below), whose sum is σ = 195041520. Its totient is φ = 32308224.

The previous prime is 81338539. The next prime is 81338561. The reversal of 81338560 is 6583318.

It is a happy number.

It is a super-2 number, since 2×81338560² = 13231922685747200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81338561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49431 + ... + 51049.

Almost surely, 2^81338560 is an apocalyptic number.

81338560 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 81338560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97520760).

81338560 is an abundant number, since it is smaller than the sum of its proper divisors (113702960).

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

81338560 is a wasteful number, since it uses less digits than its factorization.

81338560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1793 (or 1783 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 81338560 is about 9018.7892757288. The cubic root of 81338560 is about 433.2768578602.

The spelling of 81338560 in words is "eighty-one million, three hundred thirty-eight thousand, five hundred sixty".