6650722121 has 2 divisors, whose sum is σ = 6650722122. Its totient is φ = 6650722120.

The previous prime is 6650722109. The next prime is 6650722147. The reversal of 6650722121 is 1212270566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6551121721 + 99600400 = 80939^2 + 9980^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6650722121 is a prime.

It is not a weakly prime, because it can be changed into another prime (6650722181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3325361060 + 3325361061.

It is an arithmetic number, because the mean of its divisors is an integer number (3325361061).

Almost surely, 2^6650722121 is an apocalyptic number.

It is an amenable number.

6650722121 is a deficient number, since it is larger than the sum of its proper divisors (1).

6650722121 is an equidigital number, since it uses as much as digits as its factorization.

6650722121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 6650722121 is about 81551.9596392386. The cubic root of 6650722121 is about 1880.5704207854.

Adding to 6650722121 its reverse (1212270566), we get a palindrome (7862992687).

The spelling of 6650722121 in words is "six billion, six hundred fifty million, seven hundred twenty-two thousand, one hundred twenty-one".