6689989 has 2 divisors, whose sum is σ = 6689990. Its totient is φ = 6689988.

The previous prime is 6689971. The next prime is 6689999. The reversal of 6689989 is 9899866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6502500 + 187489 = 2550^2 + 433^2 .

It is a cyclic number.

It is not a de Polignac number, because 6689989 - 2¹⁷ = 6558917 is a prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6689909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3344994 + 3344995.

It is an arithmetic number, because the mean of its divisors is an integer number (3344995).

Almost surely, 2^6689989 is an apocalyptic number.

It is an amenable number.

6689989 is a deficient number, since it is larger than the sum of its proper divisors (1).

6689989 is an equidigital number, since it uses as much as digits as its factorization.

6689989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1679616, while the sum is 55.

The square root of 6689989 is about 2586.5013048518. The cubic root of 6689989 is about 188.4264219025.

The spelling of 6689989 in words is "six million, six hundred eighty-nine thousand, nine hundred eighty-nine".