21201212212120 has 16 divisors (see below), whose sum is σ = 47702727477360. Its totient is φ = 8480484884832.

The previous prime is 21201212212109. The next prime is 21201212212127. The reversal of 21201212212120 is 2121221210212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201212212127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 265015152612 + ... + 265015152691.

It is an arithmetic number, because the mean of its divisors is an integer number (2981420467335).

Almost surely, 2^{21201212212120} is an apocalyptic number.

21201212212120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21201212212120 is an abundant number, since it is smaller than the sum of its proper divisors (26501515265240).

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

21201212212120 is a wasteful number, since it uses less digits than its factorization.

21201212212120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 530030305314 (or 530030305310 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21201212212120 its reverse (2121221210212), we get a palindrome (23322433422332).

The spelling of 21201212212120 in words is "twenty-one trillion, two hundred one billion, two hundred twelve million, two hundred twelve thousand, one hundred twenty".