6722187221 has 2 divisors, whose sum is σ = 6722187222. Its totient is φ = 6722187220.

The previous prime is 6722187193. The next prime is 6722187239. The reversal of 6722187221 is 1227812276.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6721704196 + 483025 = 81986^2 + 695^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6722187221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6722187421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3361093610 + 3361093611.

It is an arithmetic number, because the mean of its divisors is an integer number (3361093611).

Almost surely, 2^6722187221 is an apocalyptic number.

It is an amenable number.

6722187221 is a deficient number, since it is larger than the sum of its proper divisors (1).

6722187221 is an equidigital number, since it uses as much as digits as its factorization.

6722187221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 37632, while the sum is 38.

The square root of 6722187221 is about 81988.9457244085. The cubic root of 6722187221 is about 1887.2823048259.

Adding to 6722187221 its reverse (1227812276), we get a palindrome (7949999497).

The spelling of 6722187221 in words is "six billion, seven hundred twenty-two million, one hundred eighty-seven thousand, two hundred twenty-one".