181221040 has 320 divisors, whose sum is σ = 591962112. Its totient is φ = 49766400.

The previous prime is 181221013. The next prime is 181221043. The reversal of 181221040 is 40122181.

It is a happy number.

181221040 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 181220999 and 181221017.

It is not an unprimeable number, because it can be changed into a prime (181221043) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2482444 + ... + 2482516.

Almost surely, 2^181221040 is an apocalyptic number.

181221040 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 181221040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (295981056).

181221040 is an abundant number, since it is smaller than the sum of its proper divisors (410741072).

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

181221040 is a wasteful number, since it uses less digits than its factorization.

181221040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148 (or 142 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 181221040 is about 13461.8364274716. The cubic root of 181221040 is about 565.8954553088.

The spelling of 181221040 in words is "one hundred eighty-one million, two hundred twenty-one thousand, forty".