181972224 has 144 divisors (see below), whose sum is σ = 615162240. Its totient is φ = 51978240.

The previous prime is 181972223. The next prime is 181972261. The reversal of 181972224 is 422279181.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×181972224² = 66227780615012352, which contains 22 as substring.

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 and also a Zuckerman number because it is divisible by the product of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181972223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46504 + ... + 50264.

It is an arithmetic number, because the mean of its divisors is an integer number (4271960).

Almost surely, 2^181972224 is an apocalyptic number.

181972224 is a gapful number since it is divisible by the number (14) 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 181972224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (307581120).

181972224 is an abundant number, since it is smaller than the sum of its proper divisors (433190016).

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

181972224 is an equidigital number, since it uses as much as digits as its factorization.

181972224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3793 (or 3773 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 181972224 is about 13489.7080769007. The cubic root of 181972224 is about 566.6762800368.

The spelling of 181972224 in words is "one hundred eighty-one million, nine hundred seventy-two thousand, two hundred twenty-four".