6681551 has 4 divisors (see below), whose sum is σ = 6807672. Its totient is φ = 6555432.

The previous prime is 6681547. The next prime is 6681557. The reversal of 6681551 is 1551866.

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: 1551866 = 2 ⋅775933.

It is a cyclic number.

It is not a de Polignac number, because 6681551 - 2² = 6681547 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6681557) 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, 62981 + ... + 63086.

It is an arithmetic number, because the mean of its divisors is an integer number (1701918).

Almost surely, 2^6681551 is an apocalyptic number.

6681551 is a deficient number, since it is larger than the sum of its proper divisors (126121).

6681551 is a wasteful number, since it uses less digits than its factorization.

6681551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126120.

The product of its digits is 7200, while the sum is 32.

The square root of 6681551 is about 2584.8696292076. The cubic root of 6681551 is about 188.3471686045.

It can be divided in two parts, 66815 and 51, that added together give a palindrome (66866).

The spelling of 6681551 in words is "six million, six hundred eighty-one thousand, five hundred fifty-one".