222520021 has 4 divisors (see below), whose sum is σ = 235609452. Its totient is φ = 209430592.

The previous prime is 222520013. The next prime is 222520031. The reversal of 222520021 is 120025222.

222520021 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.

It can be written as a sum of positive squares in 2 ways, for example, as 206956996 + 15563025 = 14386^2 + 3945^2 .

It is a cyclic number.

It is not a de Polignac number, because 222520021 - 2³ = 222520013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 222519977 and 222520004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (222520031) 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, 6544690 + ... + 6544723.

It is an arithmetic number, because the mean of its divisors is an integer number (58902363).

Almost surely, 2^222520021 is an apocalyptic number.

It is an amenable number.

222520021 is a deficient number, since it is larger than the sum of its proper divisors (13089431).

222520021 is a wasteful number, since it uses less digits than its factorization.

222520021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13089430.

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 222520021 is about 14917.1049805249. The cubic root of 222520021 is about 605.9773116508.

Adding to 222520021 its reverse (120025222), we get a palindrome (342545243).

The spelling of 222520021 in words is "two hundred twenty-two million, five hundred twenty thousand, twenty-one".