21213044020 has 96 divisors (see below), whose sum is σ = 51976673280. Its totient is φ = 7121917440.

The previous prime is 21213044009. The next prime is 21213044029. The reversal of 21213044020 is 2044031212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213044029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1950237 + ... + 1961083.

It is an arithmetic number, because the mean of its divisors is an integer number (541423680).

Almost surely, 2^21213044020 is an apocalyptic number.

21213044020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21213044020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25988336640).

21213044020 is an abundant number, since it is smaller than the sum of its proper divisors (30763629260).

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

21213044020 is a wasteful number, since it uses less digits than its factorization.

21213044020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11153 (or 11151 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 21213044020 its reverse (2044031212), we get a palindrome (23257075232).

The spelling of 21213044020 in words is "twenty-one billion, two hundred thirteen million, forty-four thousand, twenty".