6636561 has 4 divisors (see below), whose sum is σ = 8848752. Its totient is φ = 4424372.

The previous prime is 6636559. The next prime is 6636571. The reversal of 6636561 is 1656366.

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 not a de Polignac number, because 6636561 - 2¹ = 6636559 is a prime.

It is a D-number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (6636571) 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, 1106091 + ... + 1106096.

It is an arithmetic number, because the mean of its divisors is an integer number (2212188).

Almost surely, 2^6636561 is an apocalyptic number.

It is an amenable number.

6636561 is a deficient number, since it is larger than the sum of its proper divisors (2212191).

6636561 is a wasteful number, since it uses less digits than its factorization.

6636561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2212190.

The product of its digits is 19440, while the sum is 33.

The square root of 6636561 is about 2576.1523635065. The cubic root of 6636561 is about 187.9234730785.

The spelling of 6636561 in words is "six million, six hundred thirty-six thousand, five hundred sixty-one".