221221207 has 4 divisors (see below), whose sum is σ = 223501936. Its totient is φ = 218940480.

The previous prime is 221221127. The next prime is 221221213. The reversal of 221221207 is 702122122.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 221221207 - 2²⁷ = 87003479 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221227207) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1140219 + ... + 1140412.

It is an arithmetic number, because the mean of its divisors is an integer number (55875484).

Almost surely, 2^221221207 is an apocalyptic number.

221221207 is a deficient number, since it is larger than the sum of its proper divisors (2280729).

221221207 is an equidigital number, since it uses as much as digits as its factorization.

221221207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2280728.

The product of its (nonzero) digits is 224, while the sum is 19.

The square root of 221221207 is about 14873.5068830454. The cubic root of 221221207 is about 604.7960125536.

Adding to 221221207 its reverse (702122122), we get a palindrome (923343329).

The spelling of 221221207 in words is "two hundred twenty-one million, two hundred twenty-one thousand, two hundred seven".