221787072 has 168 divisors, whose sum is σ = 710616816. Its totient is φ = 68179968.

The previous prime is 221787053. The next prime is 221787089. The reversal of 221787072 is 270787122.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 201628 + ... + 202724.

It is an arithmetic number, because the mean of its divisors is an integer number (4229862).

Almost surely, 2^221787072 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 221787072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (355308408).

221787072 is an abundant number, since it is smaller than the sum of its proper divisors (488829744).

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

221787072 is a wasteful number, since it uses less digits than its factorization.

221787072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1137 (or 1115 counting only the distinct ones).

The product of its (nonzero) digits is 21952, while the sum is 36.

The square root of 221787072 is about 14892.5173157529. The cubic root of 221787072 is about 605.3112457198.

Subtracting 221787072 from its reverse (270787122), we obtain a triangular number (49000050 = T₉₈₉₉).

The spelling of 221787072 in words is "two hundred twenty-one million, seven hundred eighty-seven thousand, seventy-two".