6687729 has 12 divisors (see below), whose sum is σ = 9723636. Its totient is φ = 4429152.

The previous prime is 6687701. The next prime is 6687757. The reversal of 6687729 is 9277866.

It is a happy number.

6687729 is digitally balanced in base 3 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (6687701) and next prime (6687757).

It can be written as a sum of positive squares in 2 ways, for example, as 1557504 + 5130225 = 1248^2 + 2265^2 .

It is not a de Polignac number, because 6687729 - 2¹⁵ = 6654961 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6687229) 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, 954 + ... + 3779.

It is an arithmetic number, because the mean of its divisors is an integer number (810303).

Almost surely, 2^6687729 is an apocalyptic number.

It is an amenable number.

6687729 is a deficient number, since it is larger than the sum of its proper divisors (3035907).

6687729 is a wasteful number, since it uses less digits than its factorization.

6687729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4896 (or 4893 counting only the distinct ones).

The product of its digits is 254016, while the sum is 45.

The square root of 6687729 is about 2586.0643843493. The cubic root of 6687729 is about 188.4052015549.

The spelling of 6687729 in words is "six million, six hundred eighty-seven thousand, seven hundred twenty-nine".