21388756032 has 336 divisors, whose sum is σ = 72757694464. Its totient is φ = 5878656000.

The previous prime is 21388755967. The next prime is 21388756061. The reversal of 21388756032 is 23065788312.

21388756032 is a `hidden beast` number, since 2 + 1 + 3 + 8 + 87 + 560 + 3 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (336).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 26372907 + ... + 26373717.

Almost surely, 2^21388756032 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 21388756032, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36378847232).

21388756032 is an abundant number, since it is smaller than the sum of its proper divisors (51368938432).

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

21388756032 is a wasteful number, since it uses less digits than its factorization.

21388756032 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1078 (or 1065 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 45.

The spelling of 21388756032 in words is "twenty-one billion, three hundred eighty-eight million, seven hundred fifty-six thousand, thirty-two".