21573454128 has 80 divisors (see below), whose sum is σ = 57182340096. Its totient is φ = 7004500480.

The previous prime is 21573454117. The next prime is 21573454159. The reversal of 21573454128 is 82145437512.

It is a self number, because there is not a number n which added to its sum of digits gives 21573454128.

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 15 ways as a sum of consecutive naturals, for example, 1264825 + ... + 1281767.

Almost surely, 2^21573454128 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 21573454128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28591170048).

21573454128 is an abundant number, since it is smaller than the sum of its proper divisors (35608885968).

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

21573454128 is a wasteful number, since it uses less digits than its factorization.

21573454128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17642 (or 17636 counting only the distinct ones).

The product of its digits is 268800, while the sum is 42.

The spelling of 21573454128 in words is "twenty-one billion, five hundred seventy-three million, four hundred fifty-four thousand, one hundred twenty-eight".