221220135 has 24 divisors (see below), whose sum is σ = 403631280. Its totient is φ = 111773952.

The previous prime is 221220127. The next prime is 221220137. The reversal of 221220135 is 531022122.

It is not a de Polignac number, because 221220135 - 2³ = 221220127 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221220137) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 128514 + ... + 130223.

It is an arithmetic number, because the mean of its divisors is an integer number (16817970).

Almost surely, 2^221220135 is an apocalyptic number.

221220135 is a deficient number, since it is larger than the sum of its proper divisors (182411145).

221220135 is a wasteful number, since it uses less digits than its factorization.

221220135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 258767 (or 258764 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 221220135 is about 14873.4708457710. The cubic root of 221220135 is about 604.7950356394.

Adding to 221220135 its reverse (531022122), we get a palindrome (752242257).

The spelling of 221220135 in words is "two hundred twenty-one million, two hundred twenty thousand, one hundred thirty-five".