221981760 has 756 divisors, whose sum is σ = 1051363404. Its totient is φ = 42577920.

The previous prime is 221981743. The next prime is 221981761. The reversal of 221981760 is 67189122.

It can be written as a sum of positive squares in 2 ways, for example, as 54641664 + 167340096 = 7392^2 + 12936^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221981761) by changing a digit.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 17075514 + ... + 17075526.

Almost surely, 2^221981760 is an apocalyptic number.

221981760 is a gapful number since it is divisible by the number (20) 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 221981760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (525681702).

221981760 is an abundant number, since it is smaller than the sum of its proper divisors (829381644).

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

221981760 is a wasteful number, since it uses less digits than its factorization.

221981760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72 (or 41 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The square root of 221981760 is about 14899.0523188557. The cubic root of 221981760 is about 605.4883109998.

The spelling of 221981760 in words is "two hundred twenty-one million, nine hundred eighty-one thousand, seven hundred sixty".