21021003828 has 36 divisors (see below), whose sum is σ = 57967011648. Its totient is φ = 6370001040.

The previous prime is 21021003827. The next prime is 21021003877. The reversal of 21021003828 is 82830012012.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021003823) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 26541276 + ... + 26542067.

It is an arithmetic number, because the mean of its divisors is an integer number (1610194768).

Almost surely, 2^21021003828 is an apocalyptic number.

It is an amenable number.

21021003828 is an abundant number, since it is smaller than the sum of its proper divisors (36946007820).

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

21021003828 is a wasteful number, since it uses less digits than its factorization.

21021003828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53083364 (or 53083359 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The spelling of 21021003828 in words is "twenty-one billion, twenty-one million, three thousand, eight hundred twenty-eight".