21055433655 has 16 divisors (see below), whose sum is σ = 33839769600. Its totient is φ = 11179206048.

The previous prime is 21055433653. The next prime is 21055433671. The reversal of 21055433655 is 55633455012.

It is not a de Polignac number, because 21055433655 - 2¹ = 21055433653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21055433653) 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, 3143955 + ... + 3150644.

It is an arithmetic number, because the mean of its divisors is an integer number (2114985600).

Almost surely, 2^21055433655 is an apocalyptic number.

21055433655 is a deficient number, since it is larger than the sum of its proper divisors (12784335945).

21055433655 is a wasteful number, since it uses less digits than its factorization.

21055433655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6294830.

The product of its (nonzero) digits is 270000, while the sum is 39.

Adding to 21055433655 its reverse (55633455012), we get a palindrome (76688888667).

The spelling of 21055433655 in words is "twenty-one billion, fifty-five million, four hundred thirty-three thousand, six hundred fifty-five".