21213231111020 has 72 divisors (see below), whose sum is σ = 48247597117440. Its totient is φ = 7831041154560.

The previous prime is 21213231111019. The next prime is 21213231111029. The reversal of 21213231111020 is 2011113231212.

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 = 21213231110983 and 21213231111001.

It is not an unprimeable number, because it can be changed into a prime (21213231111029) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16689200 + ... + 17915240.

It is an arithmetic number, because the mean of its divisors is an integer number (670105515520).

Almost surely, 2^{21213231111020} is an apocalyptic number.

21213231111020 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 21213231111020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24123798558720).

21213231111020 is an abundant number, since it is smaller than the sum of its proper divisors (27034366006420).

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

21213231111020 is a wasteful number, since it uses less digits than its factorization.

21213231111020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1231195 (or 1231180 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 20.

Adding to 21213231111020 its reverse (2011113231212), we get a palindrome (23224344342232).

The spelling of 21213231111020 in words is "twenty-one trillion, two hundred thirteen billion, two hundred thirty-one million, one hundred eleven thousand, twenty".