81813600 has 216 divisors, whose sum is σ = 315026712. Its totient is φ = 19814400.

The previous prime is 81813581. The next prime is 81813631. The reversal of 81813600 is 631818.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 78684 + ... + 79716.

It is an arithmetic number, because the mean of its divisors is an integer number (1458457).

Almost surely, 2^81813600 is an apocalyptic number.

81813600 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 81813600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (157513356).

81813600 is an abundant number, since it is smaller than the sum of its proper divisors (233213112).

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

81813600 is a wasteful number, since it uses less digits than its factorization.

81813600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1070 (or 1054 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 81813600 is about 9045.0870642576. The cubic root of 81813600 is about 434.1187072199.

It can be divided in two parts, 8181 and 3600, that added together give a triangular number (11781 = T₁₅₃).

The spelling of 81813600 in words is "eighty-one million, eight hundred thirteen thousand, six hundred".