21919589728 has 24 divisors (see below), whose sum is σ = 44320524192. Its totient is φ = 10663583616.

The previous prime is 21919589717. The next prime is 21919589779. The reversal of 21919589728 is 82798591912.

It is a super-2 number, since 2×21919589728² (a number of 21 digits) contains 22 as substring.

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 3 ways as a sum of consecutive naturals, for example, 9255400 + ... + 9257767.

It is an arithmetic number, because the mean of its divisors is an integer number (1846688508).

Almost surely, 2^21919589728 is an apocalyptic number.

It is an amenable number.

21919589728 is an abundant number, since it is smaller than the sum of its proper divisors (22400934464).

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

21919589728 is a wasteful number, since it uses less digits than its factorization.

21919589728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18513214 (or 18513206 counting only the distinct ones).

The product of its digits is 6531840, while the sum is 61.

The spelling of 21919589728 in words is "twenty-one billion, nine hundred nineteen million, five hundred eighty-nine thousand, seven hundred twenty-eight".