21210022020 has 48 divisors (see below), whose sum is σ = 64786978368. Its totient is φ = 5141823360.

The previous prime is 21210022013. The next prime is 21210022081. The reversal of 21210022020 is 2022001212.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21210021987 and 21210022005.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16067539 + ... + 16068858.

It is an arithmetic number, because the mean of its divisors is an integer number (1349728716).

Almost surely, 2^21210022020 is an apocalyptic number.

21210022020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21210022020 is an abundant number, since it is smaller than the sum of its proper divisors (43576956348).

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

21210022020 is a wasteful number, since it uses less digits than its factorization.

21210022020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32136420 (or 32136418 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 21210022020 its reverse (2022001212), we get a palindrome (23232023232).

The spelling of 21210022020 in words is "twenty-one billion, two hundred ten million, twenty-two thousand, twenty".