21001211121212 has 48 divisors (see below), whose sum is σ = 43129030264320. Its totient is φ = 8762065209792.

The previous prime is 21001211121211. The next prime is 21001211121229. The reversal of 21001211121212 is 21212111210012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001211121211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61541483 + ... + 61881794.

It is an arithmetic number, because the mean of its divisors is an integer number (898521463840).

Almost surely, 2^{21001211121212} is an apocalyptic number.

It is an amenable number.

21001211121212 is an abundant number, since it is smaller than the sum of its proper divisors (22127819143108).

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

21001211121212 is a wasteful number, since it uses less digits than its factorization.

21001211121212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123423450 (or 123423448 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21001211121212 its reverse (21212111210012), we get a palindrome (42213322331224).

The spelling of 21001211121212 in words is "twenty-one trillion, one billion, two hundred eleven million, one hundred twenty-one thousand, two hundred twelve".