21153534500 has 96 divisors (see below), whose sum is σ = 52882502400. Its totient is φ = 7241203200.

The previous prime is 21153534491. The next prime is 21153534551. The reversal of 21153534500 is 543535112.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2386076 + ... + 2394924.

It is an arithmetic number, because the mean of its divisors is an integer number (550859400).

Almost surely, 2^21153534500 is an apocalyptic number.

21153534500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21153534500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26441251200).

21153534500 is an abundant number, since it is smaller than the sum of its proper divisors (31728967900).

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

21153534500 is a wasteful number, since it uses less digits than its factorization.

21153534500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9558 (or 9546 counting only the distinct ones).

The product of its (nonzero) digits is 9000, while the sum is 29.

The spelling of 21153534500 in words is "twenty-one billion, one hundred fifty-three million, five hundred thirty-four thousand, five hundred".