2166221655256 has 16 divisors (see below), whose sum is σ = 4061685292200. Its totient is φ = 1083105577344.

The previous prime is 2166221655211. The next prime is 2166221655337. The reversal of 2166221655256 is 6525561226612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1522851 + ... + 2579053.

Almost surely, 2^{2166221655256} is an apocalyptic number.

It is an amenable number.

2166221655256 is a deficient number, since it is larger than the sum of its proper divisors (1895463636944).

2166221655256 is a wasteful number, since it uses less digits than its factorization.

2166221655256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1312578 (or 1312574 counting only the distinct ones).

The product of its digits is 2592000, while the sum is 49.

The spelling of 2166221655256 in words is "two trillion, one hundred sixty-six billion, two hundred twenty-one million, six hundred fifty-five thousand, two hundred fifty-six".