21020420322 has 120 divisors (see below), whose sum is σ = 52358575500. Its totient is φ = 6297730560.

The previous prime is 21020420303. The next prime is 21020420327. The reversal of 21020420322 is 22302402012.

21020420322 is a `hidden beast` number, since 210 + 2 + 0 + 420 + 32 + 2 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 20920440321 + 99980001 = 144639^2 + 9999^2 .

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 = 21020420295 and 21020420304.

It is not an unprimeable number, because it can be changed into a prime (21020420327) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 1738554 + ... + 1750602.

Almost surely, 2^21020420322 is an apocalyptic number.

21020420322 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21020420322, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26179287750).

21020420322 is an abundant number, since it is smaller than the sum of its proper divisors (31338155178).

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

21020420322 is a wasteful number, since it uses less digits than its factorization.

21020420322 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12174 (or 12154 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

Adding to 21020420322 its reverse (22302402012), we get a palindrome (43322822334).

The spelling of 21020420322 in words is "twenty-one billion, twenty million, four hundred twenty thousand, three hundred twenty-two".