21221122020012 has 144 divisors (see below), whose sum is σ = 57656881332960. Its totient is φ = 6561359437824.

The previous prime is 21221122019971. The next prime is 21221122020019. The reversal of 21221122020012 is 21002022112212.

It is a happy number.

21221122020012 is a `hidden beast` number, since 21 + 2 + 211 + 220 + 200 + 12 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21221122020019) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5289588 + ... + 8391780.

Almost surely, 2^{21221122020012} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21221122020012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28828440666480).

21221122020012 is an abundant number, since it is smaller than the sum of its proper divisors (36435759312948).

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

21221122020012 is a wasteful number, since it uses less digits than its factorization.

21221122020012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3102432 (or 3102427 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21221122020012 its reverse (21002022112212), we get a palindrome (42223144132224).

The spelling of 21221122020012 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred twenty-two million, twenty thousand, twelve".