21001023232 has 72 divisors (see below), whose sum is σ = 48021507072. Its totient is φ = 8979225600.

The previous prime is 21001023193. The next prime is 21001023269. The reversal of 21001023232 is 23232010012.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 758757 + ... + 785947.

It is an arithmetic number, because the mean of its divisors is an integer number (666965376).

Almost surely, 2^21001023232 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 21001023232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24010753536).

21001023232 is an abundant number, since it is smaller than the sum of its proper divisors (27020483840).

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

21001023232 is an equidigital number, since it uses as much as digits as its factorization.

21001023232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27645 (or 27631 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

Adding to 21001023232 its reverse (23232010012), we get a palindrome (44233033244).

The spelling of 21001023232 in words is "twenty-one billion, one million, twenty-three thousand, two hundred thirty-two".