21203042220 has 192 divisors, whose sum is σ = 66968778240. Its totient is φ = 5568558336.

The previous prime is 21203042197. The next prime is 21203042227. The reversal of 21203042220 is 2224030212.

21203042220 is a `hidden beast` number, since 21 + 203 + 0 + 422 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21203042193 and 21203042202.

It is not an unprimeable number, because it can be changed into a prime (21203042227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 20930434 + ... + 20931446.

It is an arithmetic number, because the mean of its divisors is an integer number (348795720).

Almost surely, 2^21203042220 is an apocalyptic number.

21203042220 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 21203042220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33484389120).

21203042220 is an abundant number, since it is smaller than the sum of its proper divisors (45765736020).

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

21203042220 is a wasteful number, since it uses less digits than its factorization.

21203042220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1581 (or 1573 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

Adding to 21203042220 its reverse (2224030212), we get a palindrome (23427072432).

The spelling of 21203042220 in words is "twenty-one billion, two hundred three million, forty-two thousand, two hundred twenty".