221820768 has 240 divisors, whose sum is σ = 729978480. Its totient is φ = 65608704.

The previous prime is 221820761. The next prime is 221820799. The reversal of 221820768 is 867028122.

It is a happy number.

221820768 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×221820768² = 98408906232219648, which contains 22 as substring.

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 (221820761) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 977071 + ... + 977297.

It is an arithmetic number, because the mean of its divisors is an integer number (3041577).

Almost surely, 2^221820768 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 221820768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (364989240).

221820768 is an abundant number, since it is smaller than the sum of its proper divisors (508157712).

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

221820768 is a wasteful number, since it uses less digits than its factorization.

221820768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291 (or 274 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 221820768 is about 14893.6485791763. The cubic root of 221820768 is about 605.3418990467.

The spelling of 221820768 in words is "two hundred twenty-one million, eight hundred twenty thousand, seven hundred sixty-eight".