21211212204 has 192 divisors, whose sum is σ = 68135495680. Its totient is φ = 5556729600.

The previous prime is 21211212173. The next prime is 21211212233. The reversal of 21211212204 is 40221211212.

It is a super-3 number, since 3×21211212204³ (a number of 32 digits) contains 333 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1476882 + ... + 1491174.

Almost surely, 2^21211212204 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21211212204, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34067747840).

21211212204 is an abundant number, since it is smaller than the sum of its proper divisors (46924283476).

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

21211212204 is a wasteful number, since it uses less digits than its factorization.

21211212204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14477 (or 14469 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21211212204 its reverse (40221211212), we get a palindrome (61432423416).

The spelling of 21211212204 in words is "twenty-one billion, two hundred eleven million, two hundred twelve thousand, two hundred four".