181881984 has 128 divisors (see below), whose sum is σ = 515793600. Its totient is φ = 56623104.

The previous prime is 181881983. The next prime is 181882021. The reversal of 181881984 is 489188181.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×181881984² = 66162112207552512, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (181881983) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 707584 + ... + 707840.

Almost surely, 2^181881984 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 181881984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (257896800).

181881984 is an abundant number, since it is smaller than the sum of its proper divisors (333911616).

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

181881984 is a wasteful number, since it uses less digits than its factorization.

181881984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 390 (or 378 counting only the distinct ones).

The product of its digits is 147456, while the sum is 48.

The square root of 181881984 is about 13486.3628899715. The cubic root of 181881984 is about 566.5825929864.

The spelling of 181881984 in words is "one hundred eighty-one million, eight hundred eighty-one thousand, nine hundred eighty-four".