81803280 has 160 divisors (see below), whose sum is σ = 276482304. Its totient is φ = 19888128.

The previous prime is 81803279. The next prime is 81803291. The reversal of 81803280 is 8230818.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 489757 + ... + 489923.

Almost surely, 2^81803280 is an apocalyptic number.

81803280 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 81803280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138241152).

81803280 is an abundant number, since it is smaller than the sum of its proper divisors (194679024).

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

81803280 is a wasteful number, since it uses less digits than its factorization.

81803280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 353 (or 347 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 30.

The square root of 81803280 is about 9044.5165708290. The cubic root of 81803280 is about 434.1004531503.

The spelling of 81803280 in words is "eighty-one million, eight hundred three thousand, two hundred eighty".