7211921 has 2 divisors, whose sum is σ = 7211922. Its totient is φ = 7211920.

The previous prime is 7211909. The next prime is 7211977. The reversal of 7211921 is 1291127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4456321 + 2755600 = 2111^2 + 1660^2 .

It is a cyclic number.

It is not a de Polignac number, because 7211921 - 2¹⁰ = 7210897 is a prime.

It is not a weakly prime, because it can be changed into another prime (7211521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3605960 + 3605961.

It is an arithmetic number, because the mean of its divisors is an integer number (3605961).

Almost surely, 2^7211921 is an apocalyptic number.

It is an amenable number.

7211921 is a deficient number, since it is larger than the sum of its proper divisors (1).

7211921 is an equidigital number, since it uses as much as digits as its factorization.

7211921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 252, while the sum is 23.

The square root of 7211921 is about 2685.5020014887. The cubic root of 7211921 is about 193.2043885199.

The spelling of 7211921 in words is "seven million, two hundred eleven thousand, nine hundred twenty-one".