81660200 has 48 divisors (see below), whose sum is σ = 195999360. Its totient is φ = 31608000.

The previous prime is 81660193. The next prime is 81660223. The reversal of 81660200 is 206618.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 386 + ... + 12785.

It is an arithmetic number, because the mean of its divisors is an integer number (4083320).

Almost surely, 2^81660200 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 81660200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97999680).

81660200 is an abundant number, since it is smaller than the sum of its proper divisors (114339160).

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

81660200 is a wasteful number, since it uses less digits than its factorization.

81660200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13218 (or 13209 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 81660200 is about 9036.6033441775. The cubic root of 81660200 is about 433.8472141588.

Adding to 81660200 its reverse (206618), we get a palindrome (81866818).

It can be divided in two parts, 816 and 60200, that added together give a palindrome (61016).

The spelling of 81660200 in words is "eighty-one million, six hundred sixty thousand, two hundred".