221856516 has 192 divisors, whose sum is σ = 689472000. Its totient is φ = 61641216.

The previous prime is 221856493. The next prime is 221856517. The reversal of 221856516 is 615658122.

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

Its product of digits (28800) is a multiple of the sum of its prime factors (200).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221856517) 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 63 ways as a sum of consecutive naturals, for example, 1963276 + ... + 1963388.

It is an arithmetic number, because the mean of its divisors is an integer number (3591000).

Almost surely, 2^221856516 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 221856516, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (344736000).

221856516 is an abundant number, since it is smaller than the sum of its proper divisors (467615484).

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

221856516 is a wasteful number, since it uses less digits than its factorization.

221856516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200 (or 178 counting only the distinct ones).

The product of its digits is 28800, while the sum is 36.

The square root of 221856516 is about 14894.8486397143. The cubic root of 221856516 is about 605.3744156892.

The spelling of 221856516 in words is "two hundred twenty-one million, eight hundred fifty-six thousand, five hundred sixteen".