6641415661 has 4 divisors (see below), whose sum is σ = 6795867232. Its totient is φ = 6486964092.

The previous prime is 6641415617. The next prime is 6641415689. The reversal of 6641415661 is 1665141466.

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 6641415661 - 2²⁵ = 6607861229 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6641415961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77225721 + ... + 77225806.

It is an arithmetic number, because the mean of its divisors is an integer number (1698966808).

Almost surely, 2^6641415661 is an apocalyptic number.

It is an amenable number.

6641415661 is a deficient number, since it is larger than the sum of its proper divisors (154451571).

6641415661 is a wasteful number, since it uses less digits than its factorization.

6641415661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154451570.

The product of its digits is 103680, while the sum is 40.

The square root of 6641415661 is about 81494.8811950787. The cubic root of 6641415661 is about 1879.6928407380.

The spelling of 6641415661 in words is "six billion, six hundred forty-one million, four hundred fifteen thousand, six hundred sixty-one".