21529870128 has 240 divisors, whose sum is σ = 66106636960. Its totient is φ = 6501482496.

The previous prime is 21529870111. The next prime is 21529870129. The reversal of 21529870128 is 82107892512.

21529870128 is a `hidden beast` number, since 21 + 529 + 87 + 0 + 1 + 28 = 666.

It is not an unprimeable number, because it can be changed into a prime (21529870129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 25239750 + ... + 25240602.

Almost surely, 2^21529870128 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 21529870128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33053318480).

21529870128 is an abundant number, since it is smaller than the sum of its proper divisors (44576766832).

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

21529870128 is a wasteful number, since it uses less digits than its factorization.

21529870128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1116 (or 1107 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 45.

The spelling of 21529870128 in words is "twenty-one billion, five hundred twenty-nine million, eight hundred seventy thousand, one hundred twenty-eight".