21221203432 has 128 divisors (see below), whose sum is σ = 47513692800. Its totient is φ = 8758886400.

The previous prime is 21221203429. The next prime is 21221203453. The reversal of 21221203432 is 23430212212.

It is a Harshad number since it is a multiple of its sum of digits (22).

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 31 ways as a sum of consecutive naturals, for example, 26166307 + ... + 26167117.

It is an arithmetic number, because the mean of its divisors is an integer number (371200725).

Almost surely, 2^21221203432 is an apocalyptic number.

21221203432 is a gapful number since it is divisible by the number (22) 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 21221203432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23756846400).

21221203432 is an abundant number, since it is smaller than the sum of its proper divisors (26292489368).

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

21221203432 is a wasteful number, since it uses less digits than its factorization.

21221203432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1187 (or 1183 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 22.

Adding to 21221203432 its reverse (23430212212), we get a palindrome (44651415644).

The spelling of 21221203432 in words is "twenty-one billion, two hundred twenty-one million, two hundred three thousand, four hundred thirty-two".