21043385020 has 48 divisors (see below), whose sum is σ = 53162242560. Its totient is φ = 6835143744.

The previous prime is 21043385017. The next prime is 21043385057. The reversal of 21043385020 is 2058334012.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a self number, because there is not a number n which added to its sum of digits gives 21043385020.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3952864 + ... + 3958183.

It is an arithmetic number, because the mean of its divisors is an integer number (1107546720).

Almost surely, 2^21043385020 is an apocalyptic number.

21043385020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21043385020 is an abundant number, since it is smaller than the sum of its proper divisors (32118857540).

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

21043385020 is a wasteful number, since it uses less digits than its factorization.

21043385020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7911082 (or 7911080 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The spelling of 21043385020 in words is "twenty-one billion, forty-three million, three hundred eighty-five thousand, twenty".