7227821 has 4 divisors (see below), whose sum is σ = 7236444. Its totient is φ = 7219200.

The previous prime is 7227817. The next prime is 7227823. The reversal of 7227821 is 1287227.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1287227 = 557 ⋅2311.

It can be written as a sum of positive squares in 2 ways, for example, as 4778596 + 2449225 = 2186^2 + 1565^2 .

It is a cyclic number.

It is not a de Polignac number, because 7227821 - 2² = 7227817 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7227823) 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, 2900 + ... + 4781.

It is an arithmetic number, because the mean of its divisors is an integer number (1809111).

Almost surely, 2^7227821 is an apocalyptic number.

It is an amenable number.

7227821 is a deficient number, since it is larger than the sum of its proper divisors (8623).

7227821 is an equidigital number, since it uses as much as digits as its factorization.

7227821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8622.

The product of its digits is 3136, while the sum is 29.

The square root of 7227821 is about 2688.4607120060. The cubic root of 7227821 is about 193.3462691173.

The spelling of 7227821 in words is "seven million, two hundred twenty-seven thousand, eight hundred twenty-one".