7220021 has 4 divisors (see below), whose sum is σ = 7338444. Its totient is φ = 7101600.

The previous prime is 7219997. The next prime is 7220027. The reversal of 7220021 is 1200227.

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 4157521 + 3062500 = 2039^2 + 1750^2 .

It is a cyclic number.

It is not a de Polignac number, because 7220021 - 2¹⁰ = 7218997 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 7219978 and 7220005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7220027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59120 + ... + 59241.

It is an arithmetic number, because the mean of its divisors is an integer number (1834611).

Almost surely, 2^7220021 is an apocalyptic number.

It is an amenable number.

7220021 is a deficient number, since it is larger than the sum of its proper divisors (118423).

7220021 is a wasteful number, since it uses less digits than its factorization.

7220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118422.

The product of its (nonzero) digits is 56, while the sum is 14.

The square root of 7220021 is about 2687.0096762014. The cubic root of 7220021 is about 193.2766933433.

Adding to 7220021 its reverse (1200227), we get a palindrome (8420248).

The spelling of 7220021 in words is "seven million, two hundred twenty thousand, twenty-one".