221220913 has 8 divisors (see below), whose sum is σ = 225293760. Its totient is φ = 217158960.

The previous prime is 221220907. The next prime is 221220931. The reversal of 221220913 is 319022122.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221220913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221220973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46156 + ... + 50722.

It is an arithmetic number, because the mean of its divisors is an integer number (28161720).

Almost surely, 2^221220913 is an apocalyptic number.

It is an amenable number.

221220913 is a deficient number, since it is larger than the sum of its proper divisors (4072847).

221220913 is an equidigital number, since it uses as much as digits as its factorization.

221220913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5447.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 221220913 is about 14873.4969996971. The cubic root of 221220913 is about 604.7957446315.

The spelling of 221220913 in words is "two hundred twenty-one million, two hundred twenty thousand, nine hundred thirteen".