221042121 has 24 divisors (see below), whose sum is σ = 318103296. Its totient is φ = 136377120.

The previous prime is 221042119. The next prime is 221042137. The reversal of 221042121 is 121240122.

It is not a de Polignac number, because 221042121 - 2¹ = 221042119 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 221042121.

It is not an unprimeable number, because it can be changed into a prime (221042141) 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, 46951 + ... + 51443.

It is an arithmetic number, because the mean of its divisors is an integer number (13254304).

Almost surely, 2^221042121 is an apocalyptic number.

It is an amenable number.

221042121 is a deficient number, since it is larger than the sum of its proper divisors (97061175).

221042121 is a wasteful number, since it uses less digits than its factorization.

221042121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4573 (or 4550 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 221042121 is about 14867.4853623604. The cubic root of 221042121 is about 604.6327675972.

Adding to 221042121 its reverse (121240122), we get a palindrome (342282243).

The spelling of 221042121 in words is "two hundred twenty-one million, forty-two thousand, one hundred twenty-one".