6661555 has 8 divisors (see below), whose sum is σ = 8035632. Its totient is φ = 5301408.

The previous prime is 6661553. The next prime is 6661583. The reversal of 6661555 is 5551666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6661555 - 2¹ = 6661553 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6661555.

It is not an unprimeable number, because it can be changed into a prime (6661553) 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 7 ways as a sum of consecutive naturals, for example, 2397 + ... + 4366.

It is an arithmetic number, because the mean of its divisors is an integer number (1004454).

Almost surely, 2^6661555 is an apocalyptic number.

6661555 is a deficient number, since it is larger than the sum of its proper divisors (1374077).

6661555 is a wasteful number, since it uses less digits than its factorization.

6661555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6965.

The product of its digits is 27000, while the sum is 34.

The square root of 6661555 is about 2580.9988376596. The cubic root of 6661555 is about 188.1590908517.

The spelling of 6661555 in words is "six million, six hundred sixty-one thousand, five hundred fifty-five".