221221460 has 12 divisors (see below), whose sum is σ = 464565108. Its totient is φ = 88488576.

The previous prime is 221221457. The next prime is 221221499. The reversal of 221221460 is 64122122.

It is a happy number.

221221460 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 47087044 + 174134416 = 6862^2 + 13196^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 11061073 = 221221460 / (2 + 2 + 1 + 2 + 2 + 1 + 4 + 6 + 0).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5530517 + ... + 5530556.

It is an arithmetic number, because the mean of its divisors is an integer number (38713759).

Almost surely, 2^221221460 is an apocalyptic number.

221221460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221221460 is an abundant number, since it is smaller than the sum of its proper divisors (243343648).

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

221221460 is a wasteful number, since it uses less digits than its factorization.

221221460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11061082 (or 11061080 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 221221460 is about 14873.5153880984. The cubic root of 221221460 is about 604.7962431121.

Adding to 221221460 its reverse (64122122), we get a palindrome (285343582).

The spelling of 221221460 in words is "two hundred twenty-one million, two hundred twenty-one thousand, four hundred sixty".