2155664444221 has 8 divisors (see below), whose sum is σ = 2184634517120. Its totient is φ = 2126736451008.

The previous prime is 2155664444209. The next prime is 2155664444231. The reversal of 2155664444221 is 1224444665512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2155664444221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2155664444231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10416771 + ... + 10621696.

It is an arithmetic number, because the mean of its divisors is an integer number (273079314640).

Almost surely, 2^{2155664444221} is an apocalyptic number.

It is an amenable number.

2155664444221 is a deficient number, since it is larger than the sum of its proper divisors (28970072899).

2155664444221 is a wasteful number, since it uses less digits than its factorization.

2155664444221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21039843.

The product of its digits is 1843200, while the sum is 46.

The spelling of 2155664444221 in words is "two trillion, one hundred fifty-five billion, six hundred sixty-four million, four hundred forty-four thousand, two hundred twenty-one".