221421220 has 24 divisors (see below), whose sum is σ = 479985408. Its totient is φ = 85711200.

The previous prime is 221421173. The next prime is 221421241. The reversal of 221421220 is 22124122.

221421220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 221421194 and 221421203.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 177946 + ... + 179185.

It is an arithmetic number, because the mean of its divisors is an integer number (19999392).

Almost surely, 2^221421220 is an apocalyptic number.

221421220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221421220 is an abundant number, since it is smaller than the sum of its proper divisors (258564188).

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

221421220 is a wasteful number, since it uses less digits than its factorization.

221421220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 357171 (or 357169 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 221421220 is about 14880.2291649020. The cubic root of 221421220 is about 604.9782293011.

Adding to 221421220 its reverse (22124122), we get a palindrome (243545342).

The spelling of 221421220 in words is "two hundred twenty-one million, four hundred twenty-one thousand, two hundred twenty".