21121220221002 has 96 divisors (see below), whose sum is σ = 50644676459520. Its totient is φ = 6308447184000.

The previous prime is 21121220220907. The next prime is 21121220221007. The reversal of 21121220221002 is 20012202212112.

It is a happy number.

21121220221002 is a `hidden beast` number, since 211 + 21 + 220 + 2 + 210 + 0 + 2 = 666.

It is a super-2 number, since 2×21121220221002² (a number of 27 digits) contains 22 as substring.

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 (21121220221007) 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, 1560252 + ... + 6684072.

It is an arithmetic number, because the mean of its divisors is an integer number (527548713120).

Almost surely, 2^{21121220221002} is an apocalyptic number.

21121220221002 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21121220221002, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25322338229760).

21121220221002 is an abundant number, since it is smaller than the sum of its proper divisors (29523456238518).

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

21121220221002 is a wasteful number, since it uses less digits than its factorization.

21121220221002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5124140 (or 5124137 counting only the distinct ones).

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

Adding to 21121220221002 its reverse (20012202212112), we get a palindrome (41133422433114).

The spelling of 21121220221002 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twenty million, two hundred twenty-one thousand, two".