6687749 has 12 divisors (see below), whose sum is σ = 7224324. Its totient is φ = 6188544.

The previous prime is 6687701. The next prime is 6687757. The reversal of 6687749 is 9477866.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 21025 + 6666724 = 145^2 + 2582^2 .

It is not a de Polignac number, because 6687749 - 2²⁰ = 5639173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6687049) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20939 + ... + 21255.

It is an arithmetic number, because the mean of its divisors is an integer number (602027).

Almost surely, 2^6687749 is an apocalyptic number.

It is an amenable number.

6687749 is a deficient number, since it is larger than the sum of its proper divisors (536575).

6687749 is a wasteful number, since it uses less digits than its factorization.

6687749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424 (or 407 counting only the distinct ones).

The product of its digits is 508032, while the sum is 47.

The square root of 6687749 is about 2586.0682512262. The cubic root of 6687749 is about 188.4053893666.

The spelling of 6687749 in words is "six million, six hundred eighty-seven thousand, seven hundred forty-nine".