6611556641 has 4 divisors (see below), whose sum is σ = 6614260992. Its totient is φ = 6608852292.

The previous prime is 6611556631. The next prime is 6611556659. The reversal of 6611556641 is 1466551166.

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 6611556641 - 2⁶ = 6611556577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6611556631) 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, 1348505 + ... + 1353398.

It is an arithmetic number, because the mean of its divisors is an integer number (1653565248).

Almost surely, 2^6611556641 is an apocalyptic number.

It is an amenable number.

6611556641 is a deficient number, since it is larger than the sum of its proper divisors (2704351).

6611556641 is a wasteful number, since it uses less digits than its factorization.

6611556641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2704350.

The product of its digits is 129600, while the sum is 41.

The square root of 6611556641 is about 81311.4791465510. The cubic root of 6611556641 is about 1876.8716496272.

The spelling of 6611556641 in words is "six billion, six hundred eleven million, five hundred fifty-six thousand, six hundred forty-one".