6581681 has 4 divisors (see below), whose sum is σ = 6590832. Its totient is φ = 6572532.

The previous prime is 6581633. The next prime is 6581683. The reversal of 6581681 is 1861856.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6581681 is a prime.

It is a super-2 number, since 2×6581681² = 86637049571522, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6581683) 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, 3395 + ... + 4968.

It is an arithmetic number, because the mean of its divisors is an integer number (1647708).

Almost surely, 2^6581681 is an apocalyptic number.

It is an amenable number.

6581681 is a deficient number, since it is larger than the sum of its proper divisors (9151).

6581681 is an equidigital number, since it uses as much as digits as its factorization.

6581681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9150.

The product of its digits is 11520, while the sum is 35.

The square root of 6581681 is about 2565.4787077659. The cubic root of 6581681 is about 187.4040374132.

The spelling of 6581681 in words is "six million, five hundred eighty-one thousand, six hundred eighty-one".