81330320 has 40 divisors (see below), whose sum is σ = 192309120. Its totient is φ = 31978880.

The previous prime is 81330313. The next prime is 81330343. The reversal of 81330320 is 2303318.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×81330320² = 13229241902604800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 81330292 and 81330301.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3896 + ... + 13335.

It is an arithmetic number, because the mean of its divisors is an integer number (4807728).

Almost surely, 2^81330320 is an apocalyptic number.

81330320 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81330320 is an abundant number, since it is smaller than the sum of its proper divisors (110978800).

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

81330320 is a wasteful number, since it uses less digits than its factorization.

81330320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17303 (or 17297 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 81330320 is about 9018.3324400911. The cubic root of 81330320 is about 433.2622263338.

Adding to 81330320 its reverse (2303318), we get a palindrome (83633638).

The spelling of 81330320 in words is "eighty-one million, three hundred thirty thousand, three hundred twenty".