21751936724 has 72 divisors (see below), whose sum is σ = 45015243840. Its totient is φ = 9168090624.

The previous prime is 21751936673. The next prime is 21751936769. The reversal of 21751936724 is 42763915712.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12198737 + ... + 12200519.

It is an arithmetic number, because the mean of its divisors is an integer number (625211720).

Almost surely, 2^21751936724 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21751936724, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22507621920).

21751936724 is an abundant number, since it is smaller than the sum of its proper divisors (23263307116).

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

21751936724 is a wasteful number, since it uses less digits than its factorization.

21751936724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2797 (or 2788 counting only the distinct ones).

The product of its digits is 635040, while the sum is 47.

The spelling of 21751936724 in words is "twenty-one billion, seven hundred fifty-one million, nine hundred thirty-six thousand, seven hundred twenty-four".