181881216 has 192 divisors, whose sum is σ = 590653440. Its totient is φ = 53222400.

The previous prime is 181881191. The next prime is 181881239. The reversal of 181881216 is 612188181.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (192).

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

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 392601 + ... + 393063.

It is an arithmetic number, because the mean of its divisors is an integer number (3076320).

Almost surely, 2^181881216 is an apocalyptic number.

181881216 is a gapful number since it is divisible by the number (16) 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 181881216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (295326720).

181881216 is an abundant number, since it is smaller than the sum of its proper divisors (408772224).

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

181881216 is a wasteful number, since it uses less digits than its factorization.

181881216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 525 (or 510 counting only the distinct ones).

The product of its digits is 6144, while the sum is 36.

The square root of 181881216 is about 13486.3344167346. The cubic root of 181881216 is about 566.5817955169.

The spelling of 181881216 in words is "one hundred eighty-one million, eight hundred eighty-one thousand, two hundred sixteen".