221021210 has 8 divisors (see below), whose sum is σ = 397838196. Its totient is φ = 88408480.

The previous prime is 221021197. The next prime is 221021221. The reversal of 221021210 is 12120122.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 219069601 + 1951609 = 14801^2 + 1397^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 221021191 and 221021200.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11051051 + ... + 11051070.

Almost surely, 2^221021210 is an apocalyptic number.

221021210 is a deficient number, since it is larger than the sum of its proper divisors (176816986).

221021210 is a wasteful number, since it uses less digits than its factorization.

221021210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22102128.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 221021210 is about 14866.7820997013. The cubic root of 221021210 is about 604.6137005306.

Adding to 221021210 its reverse (12120122), we get a palindrome (233141332).

The spelling of 221021210 in words is "two hundred twenty-one million, twenty-one thousand, two hundred ten".