81368280 has 256 divisors, whose sum is σ = 317952000. Its totient is φ = 18123264.

The previous prime is 81368269. The next prime is 81368281. The reversal of 81368280 is 8286318.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81368281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 355206 + ... + 355434.

It is an arithmetic number, because the mean of its divisors is an integer number (1242000).

Almost surely, 2^81368280 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81368280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (158976000).

81368280 is an abundant number, since it is smaller than the sum of its proper divisors (236583720).

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

81368280 is a wasteful number, since it uses less digits than its factorization.

81368280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303 (or 293 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 81368280 is about 9020.4367965193. The cubic root of 81368280 is about 433.3296225849.

The spelling of 81368280 in words is "eighty-one million, three hundred sixty-eight thousand, two hundred eighty".