7121321 has 2 divisors, whose sum is σ = 7121322. Its totient is φ = 7121320.

The previous prime is 7121267. The next prime is 7121339. The reversal of 7121321 is 1231217.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3841600 + 3279721 = 1960^2 + 1811^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7121321 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 7121321.

It is not a weakly prime, because it can be changed into another prime (7121341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3560660 + 3560661.

It is an arithmetic number, because the mean of its divisors is an integer number (3560661).

Almost surely, 2^7121321 is an apocalyptic number.

It is an amenable number.

7121321 is a deficient number, since it is larger than the sum of its proper divisors (1).

7121321 is an equidigital number, since it uses as much as digits as its factorization.

7121321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84, while the sum is 17.

The square root of 7121321 is about 2668.5803341852. The cubic root of 7121321 is about 192.3919312462.

Adding to 7121321 its reverse (1231217), we get a palindrome (8352538).

The spelling of 7121321 in words is "seven million, one hundred twenty-one thousand, three hundred twenty-one".