21540241044 has 54 divisors (see below), whose sum is σ = 63338571114. Its totient is φ = 6154354080.

The previous prime is 21540241039. The next prime is 21540241061. The reversal of 21540241044 is 44014204512.

21540241044 is a `hidden beast` number, since 215 + 402 + 4 + 1 + 0 + 44 = 666.

It can be written as a sum of positive squares in only one way, i.e., 13233741444 + 8306499600 = 115038^2 + 91140^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21540240999 and 21540241017.

It is a congruent number.

It is an unprimeable number.

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 17 ways as a sum of consecutive naturals, for example, 6103747 + ... + 6107274.

Almost surely, 2^21540241044 is an apocalyptic number.

It is an amenable number.

21540241044 is an abundant number, since it is smaller than the sum of its proper divisors (41798330070).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21540241044 is a wasteful number, since it uses less digits than its factorization.

21540241044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12211045 (or 12211033 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 27.

Adding to 21540241044 its reverse (44014204512), we get a palindrome (65554445556).

The spelling of 21540241044 in words is "twenty-one billion, five hundred forty million, two hundred forty-one thousand, forty-four".