6687581 has 4 divisors (see below), whose sum is σ = 6694464. Its totient is φ = 6680700.

The previous prime is 6687557. The next prime is 6687589. The reversal of 6687581 is 1857866.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1857866 = 2 ⋅928933.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6687581 is a prime.

It is a super-2 number, since 2×6687581² = 89447479263122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6687589) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1685 + ... + 4026.

It is an arithmetic number, because the mean of its divisors is an integer number (1673616).

Almost surely, 2^6687581 is an apocalyptic number.

It is an amenable number.

6687581 is a deficient number, since it is larger than the sum of its proper divisors (6883).

6687581 is a wasteful number, since it uses less digits than its factorization.

6687581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6882.

The product of its digits is 80640, while the sum is 41.

The square root of 6687581 is about 2586.0357692809. The cubic root of 6687581 is about 188.4038117370.

The spelling of 6687581 in words is "six million, six hundred eighty-seven thousand, five hundred eighty-one".