6556644 has 18 divisors (see below), whose sum is σ = 16573830. Its totient is φ = 2185536.

The previous prime is 6556643. The next prime is 6556651. The reversal of 6556644 is 4466556.

It is a happy number.

6556644 is a `hidden beast` number, since 6 + 5 + 5 + 6 + 644 = 666.

It can be written as a sum of positive squares in only one way, i.e., 5116644 + 1440000 = 2262^2 + 1200^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 182129 = 6556644 / (6 + 5 + 5 + 6 + 6 + 4 + 4).

It is a junction number, because it is equal to n+sod(n) for n = 6556599 and 6556608.

It is not an unprimeable number, because it can be changed into a prime (6556643) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 91029 + ... + 91100.

Almost surely, 2^6556644 is an apocalyptic number.

It is an amenable number.

6556644 is an abundant number, since it is smaller than the sum of its proper divisors (10017186).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6556644 is a wasteful number, since it uses less digits than its factorization.

6556644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182139 (or 182134 counting only the distinct ones).

The product of its digits is 86400, while the sum is 36.

The square root of 6556644 is about 2560.5944622294. The cubic root of 6556644 is about 187.1661044263.

The spelling of 6556644 in words is "six million, five hundred fifty-six thousand, six hundred forty-four".