21122121211220 has 96 divisors (see below), whose sum is σ = 46381531392000. Its totient is φ = 8064661929984.

The previous prime is 21122121211189. The next prime is 21122121211231. The reversal of 21122121211220 is 2211212122112.

It is a super-2 number, since 2×21122121211220² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21122121211192 and 21122121211201.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 851720381 + ... + 851745179.

It is an arithmetic number, because the mean of its divisors is an integer number (483140952000).

Almost surely, 2^{21122121211220} is an apocalyptic number.

21122121211220 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 21122121211220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23190765696000).

21122121211220 is an abundant number, since it is smaller than the sum of its proper divisors (25259410180780).

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

21122121211220 is a wasteful number, since it uses less digits than its factorization.

21122121211220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28617 (or 28615 counting only the distinct ones).

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

Adding to 21122121211220 its reverse (2211212122112), we get a palindrome (23333333333332).

The spelling of 21122121211220 in words is "twenty-one trillion, one hundred twenty-two billion, one hundred twenty-one million, two hundred eleven thousand, two hundred twenty".