21212120202 has 128 divisors (see below), whose sum is σ = 55357145088. Its totient is φ = 5267462400.

The previous prime is 21212120183. The next prime is 21212120257. The reversal of 21212120202 is 20202121212.

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, 609327 + ... + 643197.

It is an arithmetic number, because the mean of its divisors is an integer number (432477696).

Almost surely, 2^21212120202 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21212120202, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27678572544).

21212120202 is an abundant number, since it is smaller than the sum of its proper divisors (34145024886).

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

21212120202 is a wasteful number, since it uses less digits than its factorization.

21212120202 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33964.

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21212120202 its reverse (20202121212), we get a palindrome (41414241414).

The spelling of 21212120202 in words is "twenty-one billion, two hundred twelve million, one hundred twenty thousand, two hundred two".