21543202123212 has 72 divisors (see below), whose sum is σ = 63790260851520. Its totient is φ = 5595636913440.

The previous prime is 21543202123193. The next prime is 21543202123231. The reversal of 21543202123212 is 21232120234512.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21543202123193) and next prime (21543202123231).

It is a self number, because there is not a number n which added to its sum of digits gives 21543202123212.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1665361662 + ... + 1665374597.

It is an arithmetic number, because the mean of its divisors is an integer number (885975845160).

Almost surely, 2^{21543202123212} is an apocalyptic number.

21543202123212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21543202123212 is an abundant number, since it is smaller than the sum of its proper divisors (42247058728308).

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

21543202123212 is a wasteful number, since it uses less digits than its factorization.

21543202123212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3330736291 (or 3330736282 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

Adding to 21543202123212 its reverse (21232120234512), we get a palindrome (42775322357724).

The spelling of 21543202123212 in words is "twenty-one trillion, five hundred forty-three billion, two hundred two million, one hundred twenty-three thousand, two hundred twelve".