81284480 has 128 divisors (see below), whose sum is σ = 213269760. Its totient is φ = 29491200.

The previous prime is 81284471. The next prime is 81284503. The reversal of 81284480 is 8448218.

It is a tau number, because it is divible by the number of its divisors (128).

It is a self number, because there is not a number n which added to its sum of digits gives 81284480.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 337160 + ... + 337400.

It is an arithmetic number, because the mean of its divisors is an integer number (1666170).

Almost surely, 2^81284480 is an apocalyptic number.

81284480 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 81284480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106634880).

81284480 is an abundant number, since it is smaller than the sum of its proper divisors (131985280).

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

81284480 is a wasteful number, since it uses less digits than its factorization.

81284480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308 (or 296 counting only the distinct ones).

The product of its (nonzero) digits is 16384, while the sum is 35.

The square root of 81284480 is about 9015.7905920668. The cubic root of 81284480 is about 433.1808115429.

The spelling of 81284480 in words is "eighty-one million, two hundred eighty-four thousand, four hundred eighty".