21122121111220 has 12 divisors (see below), whose sum is σ = 44356454333604. Its totient is φ = 8448848444480.

The previous prime is 21122121111209. The next prime is 21122121111227. The reversal of 21122121111220 is 2211112122112.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 9860969087524 + 11261152023696 = 3140218^2 + 3355764^2 .

It is a super-2 number, since 2×21122121111220² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122121111227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 528053027761 + ... + 528053027800.

It is an arithmetic number, because the mean of its divisors is an integer number (3696371194467).

Almost surely, 2^{21122121111220} is an apocalyptic number.

21122121111220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21122121111220 is an abundant number, since it is smaller than the sum of its proper divisors (23234333222384).

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

21122121111220 is a wasteful number, since it uses less digits than its factorization.

21122121111220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1056106055570 (or 1056106055568 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21122121111220 its reverse (2211112122112), we get a palindrome (23333233233332).

The spelling of 21122121111220 in words is "twenty-one trillion, one hundred twenty-two billion, one hundred twenty-one million, one hundred eleven thousand, two hundred twenty".