221689440 has 192 divisors, whose sum is σ = 886878720. Its totient is φ = 50664960.

The previous prime is 221689423. The next prime is 221689441. The reversal of 221689440 is 44986122.

221689440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a junction number, because it is equal to n+sod(n) for n = 221689395 and 221689404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221689441) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 26575 + ... + 33905.

It is an arithmetic number, because the mean of its divisors is an integer number (4619160).

Almost surely, 2^221689440 is an apocalyptic number.

221689440 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 221689440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (443439360).

221689440 is an abundant number, since it is smaller than the sum of its proper divisors (665189280).

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

221689440 is a wasteful number, since it uses less digits than its factorization.

221689440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7362 (or 7348 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 221689440 is about 14889.2390671921. The cubic root of 221689440 is about 605.2224121359. Note that the first 3 decimals are identical.

The spelling of 221689440 in words is "two hundred twenty-one million, six hundred eighty-nine thousand, four hundred forty".