21211220120220 has 288 divisors, whose sum is σ = 69606912211200. Its totient is φ = 5197359218688.

The previous prime is 21211220120219. The next prime is 21211220120261. The reversal of 21211220120220 is 2202102211212.

It is a happy number.

21211220120220 is a `hidden beast` number, since 2 + 1 + 211 + 220 + 12 + 0 + 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 = 21211220120193 and 21211220120202.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1861770844 + ... + 1861782236.

It is an arithmetic number, because the mean of its divisors is an integer number (241690667400).

Almost surely, 2^{21211220120220} is an apocalyptic number.

21211220120220 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 21211220120220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34803456105600).

21211220120220 is an abundant number, since it is smaller than the sum of its proper divisors (48395692090980).

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

21211220120220 is a wasteful number, since it uses less digits than its factorization.

21211220120220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14989 (or 14984 counting only the distinct ones).

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

Adding to 21211220120220 its reverse (2202102211212), we get a palindrome (23413322331432).

The spelling of 21211220120220 in words is "twenty-one trillion, two hundred eleven billion, two hundred twenty million, one hundred twenty thousand, two hundred twenty".