6400687 has 4 divisors (see below), whose sum is σ = 6777216. Its totient is φ = 6024160.

The previous prime is 6400657. The next prime is 6400697. The reversal of 6400687 is 7860046.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7860046 = 2 ⋅3930023.

It is a cyclic number.

It is not a de Polignac number, because 6400687 - 2¹⁹ = 5876399 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6400607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 188239 + ... + 188272.

It is an arithmetic number, because the mean of its divisors is an integer number (1694304).

Almost surely, 2^6400687 is an apocalyptic number.

6400687 is a deficient number, since it is larger than the sum of its proper divisors (376529).

6400687 is a wasteful number, since it uses less digits than its factorization.

6400687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 376528.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 6400687 is about 2529.9579047881. The cubic root of 6400687 is about 185.6701963808.

The spelling of 6400687 in words is "six million, four hundred thousand, six hundred eighty-seven".