21988064756 has 12 divisors (see below), whose sum is σ = 43976129568. Its totient is φ = 9423456312.

The previous prime is 21988064731. The next prime is 21988064867. The reversal of 21988064756 is 65746088912.

It is a happy number.

21988064756 is an admirable number.

It is a hoax number, since the sum of its digits (56) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 392643986 + ... + 392644041.

It is an arithmetic number, because the mean of its divisors is an integer number (3664677464).

Almost surely, 2^21988064756 is an apocalyptic number.

It is an amenable number.

21988064756 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21988064756 is a wasteful number, since it uses less digits than its factorization.

21988064756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 785288038 (or 785288036 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 56.

The spelling of 21988064756 in words is "twenty-one billion, nine hundred eighty-eight million, sixty-four thousand, seven hundred fifty-six".