221220311 has 8 divisors (see below), whose sum is σ = 238363104. Its totient is φ = 204095520.

The previous prime is 221220301. The next prime is 221220313. The reversal of 221220311 is 113022122.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 221220311 - 2¹⁸ = 220958167 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 (221220313) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32105 + ... + 38381.

It is an arithmetic number, because the mean of its divisors is an integer number (29795388).

Almost surely, 2^221220311 is an apocalyptic number.

221220311 is a deficient number, since it is larger than the sum of its proper divisors (17142793).

221220311 is a wasteful number, since it uses less digits than its factorization.

221220311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9001.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 221220311 is about 14873.4767623444. The cubic root of 221220311 is about 604.7951960285.

Adding to 221220311 its reverse (113022122), we get a palindrome (334242433).

The spelling of 221220311 in words is "two hundred twenty-one million, two hundred twenty thousand, three hundred eleven".