7721906917 has 2 divisors, whose sum is σ = 7721906918. Its totient is φ = 7721906916.

The previous prime is 7721906887. The next prime is 7721906987. The reversal of 7721906917 is 7196091277.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5649927556 + 2071979361 = 75166^2 + 45519^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7721906917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7721906987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3860953458 + 3860953459.

It is an arithmetic number, because the mean of its divisors is an integer number (3860953459).

Almost surely, 2^7721906917 is an apocalyptic number.

It is an amenable number.

7721906917 is a deficient number, since it is larger than the sum of its proper divisors (1).

7721906917 is an equidigital number, since it uses as much as digits as its factorization.

7721906917 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 333396, while the sum is 49.

The square root of 7721906917 is about 87874.3814601275. The cubic root of 7721906917 is about 1976.5517403380.

The spelling of 7721906917 in words is "seven billion, seven hundred twenty-one million, nine hundred six thousand, nine hundred seventeen".