21011764224 has 132 divisors (see below), whose sum is σ = 61559218112. Its totient is φ = 6367088640.

The previous prime is 21011764199. The next prime is 21011764259. The reversal of 21011764224 is 42246711012.

It is a tau number, because it is divible by the number of its divisors (132).

It is a junction number, because it is equal to n+sod(n) for n = 21011764191 and 21011764200.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 343449 + ... + 399975.

Almost surely, 2^21011764224 is an apocalyptic number.

21011764224 is a gapful number since it is divisible by the number (24) 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 21011764224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30779609056).

21011764224 is an abundant number, since it is smaller than the sum of its proper divisors (40547453888).

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

21011764224 is a wasteful number, since it uses less digits than its factorization.

21011764224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56572 (or 56543 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 30.

The spelling of 21011764224 in words is "twenty-one billion, eleven million, seven hundred sixty-four thousand, two hundred twenty-four".