21306535500 has 96 divisors (see below), whose sum is σ = 62624959488. Its totient is φ = 5628600000.

The previous prime is 21306535493. The next prime is 21306535511. The reversal of 21306535500 is 553560312.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 94125 + ... + 226875.

It is an arithmetic number, because the mean of its divisors is an integer number (652343328).

Almost surely, 2^21306535500 is an apocalyptic number.

21306535500 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 21306535500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31312479744).

21306535500 is an abundant number, since it is smaller than the sum of its proper divisors (41318423988).

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

21306535500 is a wasteful number, since it uses less digits than its factorization.

21306535500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132880 (or 132868 counting only the distinct ones).

The product of its (nonzero) digits is 13500, while the sum is 30.

The spelling of 21306535500 in words is "twenty-one billion, three hundred six million, five hundred thirty-five thousand, five hundred".