21504640512 has 80 divisors (see below), whose sum is σ = 59265336240. Its totient is φ = 6921019392.

The previous prime is 21504640459. The next prime is 21504640513.

21504640512 is nontrivially palindromic in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 21504640512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21504640513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 196843 + ... + 285930.

It is an arithmetic number, because the mean of its divisors is an integer number (740816703).

Almost surely, 2^21504640512 is an apocalyptic number.

It is an amenable number.

21504640512 is an abundant number, since it is smaller than the sum of its proper divisors (37760695728).

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

21504640512 is an equidigital number, since it uses as much as digits as its factorization.

21504640512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 482823 (or 482807 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 30.

The spelling of 21504640512 in words is "twenty-one billion, five hundred four million, six hundred forty thousand, five hundred twelve".