21212120203 has 16 divisors (see below), whose sum is σ = 22046755456. Its totient is φ = 20393493120.

The previous prime is 21212120183. The next prime is 21212120257. The reversal of 21212120203 is 30202121212.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21212120203 - 2²⁹ = 20675249291 is a prime.

It is a super-2 number, since 2×21212120203² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212120273) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5394148 + ... + 5398078.

It is an arithmetic number, because the mean of its divisors is an integer number (1377922216).

Almost surely, 2^21212120203 is an apocalyptic number.

21212120203 is a deficient number, since it is larger than the sum of its proper divisors (834635253).

21212120203 is a wasteful number, since it uses less digits than its factorization.

21212120203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5914.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21212120203 its reverse (30202121212), we get a palindrome (51414241415).

It can be divided in two parts, 212121 and 20203, that added together give a square (232324 = 482²).

The spelling of 21212120203 in words is "twenty-one billion, two hundred twelve million, one hundred twenty thousand, two hundred three".