81280320 has 224 divisors, whose sum is σ = 289681920. Its totient is φ = 19138560.

The previous prime is 81280307. The next prime is 81280333. The reversal of 81280320 is 2308218.

It is an interprime number because it is at equal distance from previous prime (81280307) and next prime (81280333).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 453991 + ... + 454169.

Almost surely, 2^81280320 is an apocalyptic number.

81280320 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 81280320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (144840960).

81280320 is an abundant number, since it is smaller than the sum of its proper divisors (208401600).

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

81280320 is a wasteful number, since it uses less digits than its factorization.

81280320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253 (or 243 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 81280320 is about 9015.5598827804. The cubic root of 81280320 is about 433.1734216004.

Adding to 81280320 its reverse (2308218), we get a palindrome (83588538).

The spelling of 81280320 in words is "eighty-one million, two hundred eighty thousand, three hundred twenty".