2156643255563 has 4 divisors (see below), whose sum is σ = 2156647006680. Its totient is φ = 2156639504448.

The previous prime is 2156643255551. The next prime is 2156643255583. The reversal of 2156643255563 is 3655523466512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2156643255563 - 2¹² = 2156643251467 is a prime.

It is a super-2 number, since 2×2156643255563² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2156643255583) 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, 812198 + ... + 2230011.

It is an arithmetic number, because the mean of its divisors is an integer number (539161751670).

Almost surely, 2^{2156643255563} is an apocalyptic number.

2156643255563 is a deficient number, since it is larger than the sum of its proper divisors (3751117).

2156643255563 is an equidigital number, since it uses as much as digits as its factorization.

2156643255563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3751116.

The product of its digits is 19440000, while the sum is 53.

The spelling of 2156643255563 in words is "two trillion, one hundred fifty-six billion, six hundred forty-three million, two hundred fifty-five thousand, five hundred sixty-three".