21011222012220 has 240 divisors, whose sum is σ = 72019063581696. Its totient is φ = 5085554544000.

The previous prime is 21011222012213. The next prime is 21011222012243. The reversal of 21011222012220 is 2221022211012.

It is a happy number.

21011222012220 is a `hidden beast` number, since 210 + 1 + 1 + 2 + 220 + 12 + 220 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 21011222012193 and 21011222012202.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 10310125 + ... + 12178715.

Almost surely, 2^{21011222012220} is an apocalyptic number.

21011222012220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21011222012220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36009531790848).

21011222012220 is an abundant number, since it is smaller than the sum of its proper divisors (51007841569476).

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

21011222012220 is a wasteful number, since it uses less digits than its factorization.

21011222012220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1869254 (or 1869243 counting only the distinct ones).

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

Adding to 21011222012220 its reverse (2221022211012), we get a palindrome (23232244223232).

The spelling of 21011222012220 in words is "twenty-one trillion, eleven billion, two hundred twenty-two million, twelve thousand, two hundred twenty".