6687997909 has 2 divisors, whose sum is σ = 6687997910. Its totient is φ = 6687997908.

The previous prime is 6687997847. The next prime is 6687997919. The reversal of 6687997909 is 9097997866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6372828900 + 315169009 = 79830^2 + 17753^2 .

It is a cyclic number.

It is not a de Polignac number, because 6687997909 - 2⁷ = 6687997781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6687997919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3343998954 + 3343998955.

It is an arithmetic number, because the mean of its divisors is an integer number (3343998955).

Almost surely, 2^6687997909 is an apocalyptic number.

It is an amenable number.

6687997909 is a deficient number, since it is larger than the sum of its proper divisors (1).

6687997909 is an equidigital number, since it uses as much as digits as its factorization.

6687997909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 92588832, while the sum is 70.

The square root of 6687997909 is about 81780.1804167734. The cubic root of 6687997909 is about 1884.0772673574.

The spelling of 6687997909 in words is "six billion, six hundred eighty-seven million, nine hundred ninety-seven thousand, nine hundred nine".