21105555201 has 6 divisors (see below), whose sum is σ = 30485801970. Its totient is φ = 14070370128.

The previous prime is 21105555187. The next prime is 21105555203. The reversal of 21105555201 is 10255550112.

21105555201 is a `hidden beast` number, since 2 + 1 + 105 + 5 + 552 + 0 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 20649690000 + 455865201 = 143700^2 + 21351^2 .

It is not a de Polignac number, because 21105555201 - 2⁵ = 21105555169 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21105555203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1172530836 + ... + 1172530853.

It is an arithmetic number, because the mean of its divisors is an integer number (5080966995).

Almost surely, 2^21105555201 is an apocalyptic number.

It is an amenable number.

21105555201 is a deficient number, since it is larger than the sum of its proper divisors (9380246769).

21105555201 is a wasteful number, since it uses less digits than its factorization.

21105555201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2345061695 (or 2345061692 counting only the distinct ones).

The product of its (nonzero) digits is 2500, while the sum is 27.

It can be divided in two parts, 211055 and 55201, that added together give a square (266256 = 516²).

The spelling of 21105555201 in words is "twenty-one billion, one hundred five million, five hundred fifty-five thousand, two hundred one".