7021321 has 2 divisors, whose sum is σ = 7021322. Its totient is φ = 7021320.

The previous prime is 7021319. The next prime is 7021331. The reversal of 7021321 is 1231207.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6734025 + 287296 = 2595^2 + 536^2 .

It is an emirp because it is prime and its reverse (1231207) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7021321 - 2¹ = 7021319 is a prime.

Together with 7021319, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 7021295 and 7021304.

It is not a weakly prime, because it can be changed into another prime (7021331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3510660 + 3510661.

It is an arithmetic number, because the mean of its divisors is an integer number (3510661).

Almost surely, 2^7021321 is an apocalyptic number.

It is an amenable number.

7021321 is a deficient number, since it is larger than the sum of its proper divisors (1).

7021321 is an equidigital number, since it uses as much as digits as its factorization.

7021321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 84, while the sum is 16.

The square root of 7021321 is about 2649.7775378322. Note that the first 3 decimals coincide. The cubic root of 7021321 is about 191.4871385945.

Adding to 7021321 its reverse (1231207), we get a palindrome (8252528).

The spelling of 7021321 in words is "seven million, twenty-one thousand, three hundred twenty-one".