21203203220 has 24 divisors (see below), whose sum is σ = 44687484744. Its totient is φ = 8450660736.

The previous prime is 21203203213. The next prime is 21203203243. The reversal of 21203203220 is 2230230212.

It can be written as a sum of positive squares in 4 ways, for example, as 30625156 + 21172578064 = 5534^2 + 145508^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1908107 + ... + 1919186.

It is an arithmetic number, because the mean of its divisors is an integer number (1861978531).

Almost surely, 2^21203203220 is an apocalyptic number.

21203203220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21203203220 is an abundant number, since it is smaller than the sum of its proper divisors (23484281524).

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

21203203220 is a wasteful number, since it uses less digits than its factorization.

21203203220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3827579 (or 3827577 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 17.

Adding to 21203203220 its reverse (2230230212), we get a palindrome (23433433432).

The spelling of 21203203220 in words is "twenty-one billion, two hundred three million, two hundred three thousand, two hundred twenty".