21020204244 has 24 divisors (see below), whose sum is σ = 52820000800. Its totient is φ = 6467755104.

The previous prime is 21020204243. The next prime is 21020204263. The reversal of 21020204244 is 44240202012.

It is a super-2 number, since 2×21020204244² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21020204244.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020204243) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 67372294 + ... + 67372605.

Almost surely, 2^21020204244 is an apocalyptic number.

It is an amenable number.

21020204244 is an abundant number, since it is smaller than the sum of its proper divisors (31799796556).

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

21020204244 is a wasteful number, since it uses less digits than its factorization.

21020204244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134744919 (or 134744917 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 21.

Adding to 21020204244 its reverse (44240202012), we get a palindrome (65260406256).

The spelling of 21020204244 in words is "twenty-one billion, twenty million, two hundred four thousand, two hundred forty-four".