21244004020 has 12 divisors (see below), whose sum is σ = 44612408484. Its totient is φ = 8497601600.

The previous prime is 21244003903. The next prime is 21244004057. The reversal of 21244004020 is 2040044212.

It can be written as a sum of positive squares in 2 ways, for example, as 8943863184 + 12300140836 = 94572^2 + 110906^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 531100081 + ... + 531100120.

It is an arithmetic number, because the mean of its divisors is an integer number (3717700707).

Almost surely, 2^21244004020 is an apocalyptic number.

21244004020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21244004020 is an abundant number, since it is smaller than the sum of its proper divisors (23368404464).

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

21244004020 is a wasteful number, since it uses less digits than its factorization.

21244004020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1062200210 (or 1062200208 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 19.

Adding to 21244004020 its reverse (2040044212), we get a palindrome (23284048232).

The spelling of 21244004020 in words is "twenty-one billion, two hundred forty-four million, four thousand, twenty".