6661563 has 4 divisors (see below), whose sum is σ = 8882088. Its totient is φ = 4441040.

The previous prime is 6661553. The next prime is 6661583. The reversal of 6661563 is 3651666.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6661563 - 2⁴ = 6661547 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (6661553) 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, 1110258 + ... + 1110263.

It is an arithmetic number, because the mean of its divisors is an integer number (2220522).

Almost surely, 2^6661563 is an apocalyptic number.

6661563 is a deficient number, since it is larger than the sum of its proper divisors (2220525).

6661563 is a wasteful number, since it uses less digits than its factorization.

6661563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2220524.

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

The square root of 6661563 is about 2581.0003874467. Note that the first 3 decimals coincide. The cubic root of 6661563 is about 188.1591661731.

The spelling of 6661563 in words is "six million, six hundred sixty-one thousand, five hundred sixty-three".