21000004032 has 224 divisors, whose sum is σ = 65114058240. Its totient is φ = 5849395200.

The previous prime is 21000004031. The next prime is 21000004043. The reversal of 21000004032 is 23040000012.

It is a tau number, because it is divible by the number of its divisors (224).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21000003999 and 21000004017.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000004031) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9093694 + ... + 9096002.

It is an arithmetic number, because the mean of its divisors is an integer number (290687760).

Almost surely, 2^21000004032 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 21000004032, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32557029120).

21000004032 is an abundant number, since it is smaller than the sum of its proper divisors (44114054208).

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

21000004032 is a wasteful number, since it uses less digits than its factorization.

21000004032 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2499 (or 2489 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 12.

Adding to 21000004032 its reverse (23040000012), we get a palindrome (44040004044).

The spelling of 21000004032 in words is "twenty-one billion, four thousand, thirty-two".