221000121 has 12 divisors (see below), whose sum is σ = 319356180. Its totient is φ = 147271680.

The previous prime is 221000107. The next prime is 221000137. The reversal of 221000121 is 121000122.

221000121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 53582400 + 167417721 = 7320^2 + 12939^2 .

It is not a de Polignac number, because 221000121 - 2¹¹ = 220998073 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (221000141) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 30585 + ... + 37113.

It is an arithmetic number, because the mean of its divisors is an integer number (26613015).

Almost surely, 2^221000121 is an apocalyptic number.

It is an amenable number.

221000121 is a deficient number, since it is larger than the sum of its proper divisors (98356059).

221000121 is a wasteful number, since it uses less digits than its factorization.

221000121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10296 (or 10293 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 221000121 is about 14866.0728169884. The cubic root of 221000121 is about 604.5944699420.

Adding to 221000121 its reverse (121000122), we get a palindrome (342000243).

Subtracting from 221000121 its reverse (121000122), we obtain a palindrome (99999999).

The spelling of 221000121 in words is "two hundred twenty-one million, one hundred twenty-one", and thus it is an aban number.