21201122121212 has 24 divisors (see below), whose sum is σ = 40475195569200. Its totient is φ = 9636796056960.

The previous prime is 21201122121211. The next prime is 21201122121241. The reversal of 21201122121212 is 21212122110212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201122121211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3771914 + ... + 7525262.

It is an arithmetic number, because the mean of its divisors is an integer number (1686466482050).

Almost surely, 2^{21201122121212} is an apocalyptic number.

21201122121212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21201122121212 is a deficient number, since it is larger than the sum of its proper divisors (19274073447988).

21201122121212 is a wasteful number, since it uses less digits than its factorization.

21201122121212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3881741 (or 3881739 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 21201122121212 its reverse (21212122110212), we get a palindrome (42413244231424).

The spelling of 21201122121212 in words is "twenty-one trillion, two hundred one billion, one hundred twenty-two million, one hundred twenty-one thousand, two hundred twelve".