6651665989 has 2 divisors, whose sum is σ = 6651665990. Its totient is φ = 6651665988.

The previous prime is 6651665983. The next prime is 6651666067. The reversal of 6651665989 is 9895661566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4550177025 + 2101488964 = 67455^2 + 45842^2 .

It is a cyclic number.

It is not a de Polignac number, because 6651665989 - 2³ = 6651665981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6651665981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3325832994 + 3325832995.

It is an arithmetic number, because the mean of its divisors is an integer number (3325832995).

Almost surely, 2^6651665989 is an apocalyptic number.

It is an amenable number.

6651665989 is a deficient number, since it is larger than the sum of its proper divisors (1).

6651665989 is an equidigital number, since it uses as much as digits as its factorization.

6651665989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20995200, while the sum is 61.

The square root of 6651665989 is about 81557.7463457641. The cubic root of 6651665989 is about 1880.6593798612.

The spelling of 6651665989 in words is "six billion, six hundred fifty-one million, six hundred sixty-five thousand, nine hundred eighty-nine".