221440420 has 24 divisors (see below), whose sum is σ = 465494904. Its totient is φ = 88486656.

The previous prime is 221440391. The next prime is 221440423. The reversal of 221440420 is 24044122.

221440420 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 10086976 + 211353444 = 3176^2 + 14538^2 .

It is not an unprimeable number, because it can be changed into a prime (221440423) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16894 + ... + 26986.

It is an arithmetic number, because the mean of its divisors is an integer number (19395621).

Almost surely, 2^221440420 is an apocalyptic number.

221440420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221440420 is an abundant number, since it is smaller than the sum of its proper divisors (244054484).

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

221440420 is a wasteful number, since it uses less digits than its factorization.

221440420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11199 (or 11197 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 19.

The square root of 221440420 is about 14880.8743022714. The cubic root of 221440420 is about 604.9957151986.

Adding to 221440420 its reverse (24044122), we get a palindrome (245484542).

The spelling of 221440420 in words is "two hundred twenty-one million, four hundred forty thousand, four hundred twenty".