221401306 has 12 divisors (see below), whose sum is σ = 386322858. Its totient is φ = 94886232.

The previous prime is 221401291. The next prime is 221401321. The reversal of 221401306 is 603104122.

It is an interprime number because it is at equal distance from previous prime (221401291) and next prime (221401321).

It can be written as a sum of positive squares in only one way, i.e., 175960225 + 45441081 = 13265^2 + 6741^2 .

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 1129501 + ... + 1129696.

Almost surely, 2^221401306 is an apocalyptic number.

221401306 is a deficient number, since it is larger than the sum of its proper divisors (164921552).

221401306 is a wasteful number, since it uses less digits than its factorization.

221401306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2259213 (or 2259206 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 221401306 is about 14879.5600069357. The cubic root of 221401306 is about 604.9600920788.

Adding to 221401306 its reverse (603104122), we get a palindrome (824505428).

The spelling of 221401306 in words is "two hundred twenty-one million, four hundred one thousand, three hundred six".