21531340024 has 16 divisors (see below), whose sum is σ = 40379058720. Its totient is φ = 10763591040.

The previous prime is 21531340013. The next prime is 21531340027. The reversal of 21531340024 is 42004313512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21531340027) 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 3 ways as a sum of consecutive naturals, for example, 215409 + ... + 299104.

It is an arithmetic number, because the mean of its divisors is an integer number (2523691170).

Almost surely, 2^21531340024 is an apocalyptic number.

It is an amenable number.

21531340024 is a deficient number, since it is larger than the sum of its proper divisors (18847718696).

21531340024 is a wasteful number, since it uses less digits than its factorization.

21531340024 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 519750 (or 519746 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

Adding to 21531340024 its reverse (42004313512), we get a palindrome (63535653536).

The spelling of 21531340024 in words is "twenty-one billion, five hundred thirty-one million, three hundred forty thousand, twenty-four".