6688861 has 4 divisors (see below), whose sum is σ = 6718300. Its totient is φ = 6659424.

The previous prime is 6688859. The next prime is 6688907. The reversal of 6688861 is 1688866.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1688866 = 2 ⋅844433.

It can be written as a sum of positive squares in 2 ways, for example, as 4756761 + 1932100 = 2181^2 + 1390^2 .

It is a cyclic number.

It is not a de Polignac number, because 6688861 - 2¹ = 6688859 is a prime.

It is a super-2 number, since 2×6688861² = 89481722954642, 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 (6688831) 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, 14376 + ... + 14833.

It is an arithmetic number, because the mean of its divisors is an integer number (1679575).

Almost surely, 2^6688861 is an apocalyptic number.

It is an amenable number.

6688861 is a deficient number, since it is larger than the sum of its proper divisors (29439).

6688861 is a wasteful number, since it uses less digits than its factorization.

6688861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29438.

The product of its digits is 110592, while the sum is 43.

The square root of 6688861 is about 2586.2832404824. The cubic root of 6688861 is about 188.4158311052.

The spelling of 6688861 in words is "six million, six hundred eighty-eight thousand, eight hundred sixty-one".