6921664055 has 16 divisors (see below), whose sum is σ = 8466158880. Its totient is φ = 5430642048.

The previous prime is 6921664051. The next prime is 6921664093. The reversal of 6921664055 is 5504661296.

It is a cyclic number.

It is not a de Polignac number, because 6921664055 - 2² = 6921664051 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 6921663997 and 6921664015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6921664051) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1017656 + ... + 1024434.

It is an arithmetic number, because the mean of its divisors is an integer number (529134930).

Almost surely, 2^6921664055 is an apocalyptic number.

6921664055 is a deficient number, since it is larger than the sum of its proper divisors (1544494825).

6921664055 is a wasteful number, since it uses less digits than its factorization.

6921664055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10690.

The product of its (nonzero) digits is 388800, while the sum is 44.

The square root of 6921664055 is about 83196.5387200694. The cubic root of 6921664055 is about 1905.7686227231.

The spelling of 6921664055 in words is "six billion, nine hundred twenty-one million, six hundred sixty-four thousand, fifty-five".