21389569128 has 256 divisors, whose sum is σ = 62596800000. Its totient is φ = 6760765440.

The previous prime is 21389569073. The next prime is 21389569139. The reversal of 21389569128 is 82196598312.

21389569128 is a `hidden beast` number, since 21 + 38 + 9 + 569 + 1 + 28 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 93404118 + ... + 93404346.

It is an arithmetic number, because the mean of its divisors is an integer number (244518750).

Almost surely, 2^21389569128 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 21389569128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31298400000).

21389569128 is an abundant number, since it is smaller than the sum of its proper divisors (41207230872).

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

21389569128 is a wasteful number, since it uses less digits than its factorization.

21389569128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 537 (or 527 counting only the distinct ones).

The product of its digits is 1866240, while the sum is 54.

The spelling of 21389569128 in words is "twenty-one billion, three hundred eighty-nine million, five hundred sixty-nine thousand, one hundred twenty-eight".