21003581382 has 48 divisors (see below), whose sum is σ = 48981833712. Its totient is φ = 5986733760.

The previous prime is 21003581359. The next prime is 21003581387. The reversal of 21003581382 is 28318530012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003581387) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 38928 + ... + 208620.

It is an arithmetic number, because the mean of its divisors is an integer number (1020454869).

Almost surely, 2^21003581382 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21003581382, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24490916856).

21003581382 is an abundant number, since it is smaller than the sum of its proper divisors (27978252330).

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

21003581382 is a wasteful number, since it uses less digits than its factorization.

21003581382 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170133 (or 170126 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 33.

The spelling of 21003581382 in words is "twenty-one billion, three million, five hundred eighty-one thousand, three hundred eighty-two".