181220889600 has 528 divisors, whose sum is σ = 668887545600. Its totient is φ = 48079503360.

The previous prime is 181220889571. The next prime is 181220889643. The reversal of 181220889600 is 6988022181.

It is a happy number.

181220889600 is a `hidden beast` number, since 1 + 8 + 12 + 20 + 8 + 8 + 9 + 600 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 165196252 + ... + 165197348.

Almost surely, 2^181220889600 is an apocalyptic number.

181220889600 is a gapful number since it is divisible by the number (10) 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 181220889600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (334443772800).

181220889600 is an abundant number, since it is smaller than the sum of its proper divisors (487666656000).

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

181220889600 is a wasteful number, since it uses less digits than its factorization.

181220889600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1375 (or 1346 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 45.

The spelling of 181220889600 in words is "one hundred eighty-one billion, two hundred twenty million, eight hundred eighty-nine thousand, six hundred".