81233280 has 160 divisors (see below), whose sum is σ = 290283840. Its totient is φ = 21648384.

The previous prime is 81233233. The next prime is 81233281. The reversal of 81233280 is 8233218.

It is a tau number, because it is divible by the number of its divisors (160).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81233281) by changing a digit.

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 19 ways as a sum of consecutive naturals, for example, 51057 + ... + 52623.

It is an arithmetic number, because the mean of its divisors is an integer number (1814274).

Almost surely, 2^81233280 is an apocalyptic number.

81233280 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 81233280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145141920).

81233280 is an abundant number, since it is smaller than the sum of its proper divisors (209050560).

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

81233280 is a wasteful number, since it uses less digits than its factorization.

81233280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1598 (or 1577 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 81233280 is about 9012.9506822128. The cubic root of 81233280 is about 433.0898408521.

Adding to 81233280 its reverse (8233218), we get a palindrome (89466498).

The spelling of 81233280 in words is "eighty-one million, two hundred thirty-three thousand, two hundred eighty".