221355121 has 4 divisors (see below), whose sum is σ = 238382452. Its totient is φ = 204327792.

The previous prime is 221355091. The next prime is 221355131. The reversal of 221355121 is 121553122.

221355121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 121553122 = 2 ⋅60776561.

It can be written as a sum of positive squares in 2 ways, for example, as 118048225 + 103306896 = 10865^2 + 10164^2 .

It is a cyclic number.

It is not a de Polignac number, because 221355121 - 2²³ = 212966513 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221355092 and 221355101.

It is not an unprimeable number, because it can be changed into a prime (221355131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8513646 + ... + 8513671.

It is an arithmetic number, because the mean of its divisors is an integer number (59595613).

Almost surely, 2^221355121 is an apocalyptic number.

It is an amenable number.

221355121 is a deficient number, since it is larger than the sum of its proper divisors (17027331).

221355121 is a wasteful number, since it uses less digits than its factorization.

221355121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17027330.

The product of its digits is 600, while the sum is 22.

The square root of 221355121 is about 14878.0079647781. The cubic root of 221355121 is about 604.9180236355.

The spelling of 221355121 in words is "two hundred twenty-one million, three hundred fifty-five thousand, one hundred twenty-one".