81715200 has 336 divisors, whose sum is σ = 325038720. Its totient is φ = 17694720.

The previous prime is 81715189. The next prime is 81715201. The reversal of 81715200 is 251718.

It is a tau number, because it is divible by the number of its divisors (336).

It is a super-2 number, since 2×81715200² = 13354747822080000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81715201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4300791 + ... + 4300809.

Almost surely, 2^81715200 is an apocalyptic number.

81715200 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 81715200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (162519360).

81715200 is an abundant number, since it is smaller than the sum of its proper divisors (243323520).

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

81715200 is a wasteful number, since it uses less digits than its factorization.

81715200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65 (or 36 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 24.

The square root of 81715200 is about 9039.6460107683. The cubic root of 81715200 is about 433.9445942848.

Adding to 81715200 its reverse (251718), we get a palindrome (81966918).

The spelling of 81715200 in words is "eighty-one million, seven hundred fifteen thousand, two hundred".