81800409600 has 2160 divisors, whose sum is σ = 396912804288. Its totient is φ = 16243752960.

The previous prime is 81800409589. The next prime is 81800409611. The reversal of 81800409600 is 690400818.

It is a happy number.

81800409600 is a `hidden beast` number, since 8 + 1 + 8 + 0 + 0 + 40 + 9 + 600 = 666.

It is an interprime number because it is at equal distance from previous prime (81800409589) and next prime (81800409611).

It is a tau number, because it is divible by the number of its divisors (2160).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 4811788792 + ... + 4811788808.

Almost surely, 2^81800409600 is an apocalyptic number.

81800409600 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 81800409600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (198456402144).

81800409600 is an abundant number, since it is smaller than the sum of its proper divisors (315112394688).

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

81800409600 is a wasteful number, since it uses less digits than its factorization.

81800409600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The spelling of 81800409600 in words is "eighty-one billion, eight hundred million, four hundred nine thousand, six hundred".