21755421444747 has 32 divisors (see below), whose sum is σ = 29403252736000. Its totient is φ = 14307013784448.

The previous prime is 21755421444737. The next prime is 21755421444781. The reversal of 21755421444747 is 74744412455712.

It is a de Polignac number, because none of the positive numbers 2^k-21755421444747 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21755421444737) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 108244953 + ... + 108445749.

It is an arithmetic number, because the mean of its divisors is an integer number (918851648000).

Almost surely, 2^{21755421444747} is an apocalyptic number.

21755421444747 is a deficient number, since it is larger than the sum of its proper divisors (7647831291253).

21755421444747 is a wasteful number, since it uses less digits than its factorization.

21755421444747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202555.

The product of its digits is 35123200, while the sum is 57.

The spelling of 21755421444747 in words is "twenty-one trillion, seven hundred fifty-five billion, four hundred twenty-one million, four hundred forty-four thousand, seven hundred forty-seven".