21212212212240 has 80 divisors (see below), whose sum is σ = 75151837557888. Its totient is φ = 4848505648128.

The previous prime is 21212212212239. The next prime is 21212212212287. The reversal of 21212212212240 is 4221221221212.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21212212212240.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6313156717 + ... + 6313160076.

Almost surely, 2^{21212212212240} is an apocalyptic number.

21212212212240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212212212240 is an abundant number, since it is smaller than the sum of its proper divisors (53939625345648).

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

21212212212240 is a wasteful number, since it uses less digits than its factorization.

21212212212240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12626316816 (or 12626316810 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 24.

Adding to 21212212212240 its reverse (4221221221212), we get a palindrome (25433433433452).

The spelling of 21212212212240 in words is "twenty-one trillion, two hundred twelve billion, two hundred twelve million, two hundred twelve thousand, two hundred forty".