21230442020 has 12 divisors (see below), whose sum is σ = 44583928284. Its totient is φ = 8492176800.

The previous prime is 21230442017. The next prime is 21230442049. The reversal of 21230442020 is 2024403212.

It can be written as a sum of positive squares in 2 ways, for example, as 5525840896 + 15704601124 = 74336^2 + 125318^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 1061522101 = 21230442020 / (2 + 1 + 2 + 3 + 0 + 4 + 4 + 2 + 0 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 21230441983 and 21230442001.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 530761031 + ... + 530761070.

It is an arithmetic number, because the mean of its divisors is an integer number (3715327357).

Almost surely, 2^21230442020 is an apocalyptic number.

21230442020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21230442020 is an abundant number, since it is smaller than the sum of its proper divisors (23353486264).

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

21230442020 is a wasteful number, since it uses less digits than its factorization.

21230442020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1061522110 (or 1061522108 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

Adding to 21230442020 its reverse (2024403212), we get a palindrome (23254845232).

The spelling of 21230442020 in words is "twenty-one billion, two hundred thirty million, four hundred forty-two thousand, twenty".