221201111 has 4 divisors (see below), whose sum is σ = 222359424. Its totient is φ = 220042800.

The previous prime is 221201083. The next prime is 221201117. The reversal of 221201111 is 111102122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 111102122 = 2 ⋅55551061.

It is a cyclic number.

It is not a de Polignac number, because 221201111 - 2⁶ = 221201047 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221201092 and 221201101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221201117) 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, 578870 + ... + 579251.

It is an arithmetic number, because the mean of its divisors is an integer number (55589856).

Almost surely, 2^221201111 is an apocalyptic number.

221201111 is a deficient number, since it is larger than the sum of its proper divisors (1158313).

221201111 is a wasteful number, since it uses less digits than its factorization.

221201111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1158312.

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 221201111 is about 14872.8313040927. The cubic root of 221201111 is about 604.7776985337. Note that the first 3 decimals are identical.

Adding to 221201111 its reverse (111102122), we get a palindrome (332303233).

The spelling of 221201111 in words is "two hundred twenty-one million, two hundred one thousand, one hundred eleven".