221155440 has 160 divisors (see below), whose sum is σ = 787449600. Its totient is φ = 50780160.

The previous prime is 221155433. The next prime is 221155453. The reversal of 221155440 is 44551122.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 221155440.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 47956 + ... + 52364.

It is an arithmetic number, because the mean of its divisors is an integer number (4921560).

Almost surely, 2^221155440 is an apocalyptic number.

221155440 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 221155440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (393724800).

221155440 is an abundant number, since it is smaller than the sum of its proper divisors (566294160).

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

221155440 is a wasteful number, since it uses less digits than its factorization.

221155440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4455 (or 4449 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 24.

The square root of 221155440 is about 14871.2958413179. The cubic root of 221155440 is about 604.7360732102.

The spelling of 221155440 in words is "two hundred twenty-one million, one hundred fifty-five thousand, four hundred forty".