223121021 has 4 divisors (see below), whose sum is σ = 224542332. Its totient is φ = 221699712.

The previous prime is 223121011. The next prime is 223121027. The reversal of 223121021 is 120121322.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 169260100 + 53860921 = 13010^2 + 7339^2 .

It is a cyclic number.

It is not a de Polignac number, because 223121021 - 2⁶ = 223120957 is a prime.

It is a super-5 number, since 5×223121021⁵ (a number of 43 digits) contains 55555 as substring. Note that it is a super-d number also for d = 3.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 223120987 and 223121005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (223121027) 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, 710420 + ... + 710733.

It is an arithmetic number, because the mean of its divisors is an integer number (56135583).

Almost surely, 2^223121021 is an apocalyptic number.

It is an amenable number.

223121021 is a deficient number, since it is larger than the sum of its proper divisors (1421311).

223121021 is a wasteful number, since it uses less digits than its factorization.

223121021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1421310.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 223121021 is about 14937.2360562455. The cubic root of 223121021 is about 606.5223786725.

Adding to 223121021 its reverse (120121322), we get a palindrome (343242343).

The spelling of 223121021 in words is "two hundred twenty-three million, one hundred twenty-one thousand, twenty-one".