21002121212022 has 72 divisors (see below), whose sum is σ = 47739512684136. Its totient is φ = 6928534412928.

The previous prime is 21002121211997. The next prime is 21002121212081. The reversal of 21002121212022 is 22021212120012.

It is a happy number.

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 = 21002121211986 and 21002121212004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 6977308 + ... + 9522975.

Almost surely, 2^{21002121212022} is an apocalyptic number.

21002121212022 is an abundant number, since it is smaller than the sum of its proper divisors (26737391472114).

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

21002121212022 is an frugal number, since it uses more digits than its factorization.

21002121212022 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16500406 (or 16500385 counting only the distinct ones).

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

Adding to 21002121212022 its reverse (22021212120012), we get a palindrome (43023333332034).

The spelling of 21002121212022 in words is "twenty-one trillion, two billion, one hundred twenty-one million, two hundred twelve thousand, twenty-two".