221153121 has 36 divisors (see below), whose sum is σ = 377735124. Its totient is φ = 124286400.

The previous prime is 221153111. The next prime is 221153167. The reversal of 221153121 is 121351122.

221153121 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 103734225 + 117418896 = 10185^2 + 10836^2 .

It is not a de Polignac number, because 221153121 - 2¹³ = 221144929 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221153094 and 221153103.

It is not an unprimeable number, because it can be changed into a prime (221153111) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 22791 + ... + 31011.

Almost surely, 2^221153121 is an apocalyptic number.

221153121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

221153121 is a deficient number, since it is larger than the sum of its proper divisors (156582003).

221153121 is a wasteful number, since it uses less digits than its factorization.

221153121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8302 (or 8292 counting only the distinct ones).

The product of its digits is 120, while the sum is 18.

The square root of 221153121 is about 14871.2178721179. The cubic root of 221153121 is about 604.7339594814.

The spelling of 221153121 in words is "two hundred twenty-one million, one hundred fifty-three thousand, one hundred twenty-one".