81802368 has 96 divisors (see below), whose sum is σ = 249301260. Its totient is φ = 25657344.

The previous prime is 81802363. The next prime is 81802381. The reversal of 81802368 is 86320818.

It can be written as a sum of positive squares in 2 ways, for example, as 69355584 + 12446784 = 8328^2 + 3528^2 .

It is a tau number, because it is divible by the number of its divisors (96).

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 (81802361) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17496 + ... + 21672.

Almost surely, 2^81802368 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 81802368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (124650630).

81802368 is an abundant number, since it is smaller than the sum of its proper divisors (167498892).

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

81802368 is a wasteful number, since it uses less digits than its factorization.

81802368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4214 (or 4199 counting only the distinct ones).

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

The square root of 81802368 is about 9044.4661534001. The cubic root of 81802368 is about 434.0988399261.

The spelling of 81802368 in words is "eighty-one million, eight hundred two thousand, three hundred sixty-eight".