6689945 has 4 divisors (see below), whose sum is σ = 8027940. Its totient is φ = 5351952.

The previous prime is 6689909. The next prime is 6689971. The reversal of 6689945 is 5499866.

6689945 is nontrivially palindromic in base 4.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3489424 + 3200521 = 1868^2 + 1789^2 .

It is a cyclic number.

It is not a de Polignac number, because 6689945 - 2⁸ = 6689689 is a prime.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 6689945.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 668990 + ... + 668999.

It is an arithmetic number, because the mean of its divisors is an integer number (2006985).

Almost surely, 2^6689945 is an apocalyptic number.

It is an amenable number.

6689945 is a deficient number, since it is larger than the sum of its proper divisors (1337995).

6689945 is a wasteful number, since it uses less digits than its factorization.

6689945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1337994.

The product of its digits is 466560, while the sum is 47.

The square root of 6689945 is about 2586.4927991394. The cubic root of 6689945 is about 188.4260088086.

The spelling of 6689945 in words is "six million, six hundred eighty-nine thousand, nine hundred forty-five".