221445420 has 48 divisors (see below), whose sum is σ = 708626688. Its totient is φ = 50616000.

The previous prime is 221445391. The next prime is 221445457. The reversal of 221445420 is 24544122.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 263206 + ... + 264045.

It is an arithmetic number, because the mean of its divisors is an integer number (14763056).

Almost surely, 2^221445420 is an apocalyptic number.

221445420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221445420 is an abundant number, since it is smaller than the sum of its proper divisors (487181268).

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

221445420 is a wasteful number, since it uses less digits than its factorization.

221445420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 527270 (or 527268 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 24.

The square root of 221445420 is about 14881.0423022045. The cubic root of 221445420 is about 605.0002686518. Note that the first 3 decimals are identical.

Adding to 221445420 its reverse (24544122), we get a palindrome (245989542).

The spelling of 221445420 in words is "two hundred twenty-one million, four hundred forty-five thousand, four hundred twenty".