21240204201 has 24 divisors (see below), whose sum is σ = 32278037064. Its totient is φ = 13441386240.

The previous prime is 21240204149. The next prime is 21240204229. The reversal of 21240204201 is 10240204212.

21240204201 is a `hidden beast` number, since 2 + 1 + 240 + 2 + 0 + 420 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1450467225 + 19789736976 = 38085^2 + 140676^2 .

It is not a de Polignac number, because 21240204201 - 2¹⁹ = 21239679913 is a prime.

It is a super-2 number, since 2×21240204201² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21240204301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 764206 + ... + 791511.

It is an arithmetic number, because the mean of its divisors is an integer number (1344918211).

Almost surely, 2^21240204201 is an apocalyptic number.

It is an amenable number.

21240204201 is a deficient number, since it is larger than the sum of its proper divisors (11037832863).

21240204201 is a wasteful number, since it uses less digits than its factorization.

21240204201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1555801 (or 1555798 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

Adding to 21240204201 its reverse (10240204212), we get a palindrome (31480408413).

The spelling of 21240204201 in words is "twenty-one billion, two hundred forty million, two hundred four thousand, two hundred one".