21243000524 has 24 divisors (see below), whose sum is σ = 38967604368. Its totient is φ = 10121448960.

The previous prime is 21243000509. The next prime is 21243000529. The reversal of 21243000524 is 42500034212.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21243000524.

It is not an unprimeable number, because it can be changed into a prime (21243000529) 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 7 ways as a sum of consecutive naturals, for example, 1499117 + ... + 1513220.

It is an arithmetic number, because the mean of its divisors is an integer number (1623650182).

Almost surely, 2^21243000524 is an apocalyptic number.

It is an amenable number.

21243000524 is a deficient number, since it is larger than the sum of its proper divisors (17724603844).

21243000524 is a wasteful number, since it uses less digits than its factorization.

21243000524 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3012425 (or 3012423 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 23.

Adding to 21243000524 its reverse (42500034212), we get a palindrome (63743034736).

The spelling of 21243000524 in words is "twenty-one billion, two hundred forty-three million, five hundred twenty-four", and thus it is an aban number.