21247748564 has 48 divisors (see below), whose sum is σ = 46175109120. Its totient is φ = 8348611680.

The previous prime is 21247748531. The next prime is 21247748603. The reversal of 21247748564 is 46584774212.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 627692 + ... + 660675.

It is an arithmetic number, because the mean of its divisors is an integer number (961981440).

Almost surely, 2^21247748564 is an apocalyptic number.

It is an amenable number.

21247748564 is an abundant number, since it is smaller than the sum of its proper divisors (24927360556).

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

21247748564 is a wasteful number, since it uses less digits than its factorization.

21247748564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1288428 (or 1288426 counting only the distinct ones).

The product of its digits is 3010560, while the sum is 50.

The spelling of 21247748564 in words is "twenty-one billion, two hundred forty-seven million, seven hundred forty-eight thousand, five hundred sixty-four".