21020221020 has 48 divisors (see below), whose sum is σ = 59004939168. Its totient is φ = 5591266560.

The previous prime is 21020220967. The next prime is 21020221031. The reversal of 21020221020 is 2012202012.

It is a super-3 number, since 3×21020221020³ (a number of 32 digits) contains 333 as substring.

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 = 21020220987 and 21020221005.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 417411 + ... + 465050.

It is an arithmetic number, because the mean of its divisors is an integer number (1229269566).

Almost surely, 2^21020221020 is an apocalyptic number.

21020221020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21020221020 is an abundant number, since it is smaller than the sum of its proper divisors (37984718148).

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

21020221020 is a wasteful number, since it uses less digits than its factorization.

21020221020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 882870 (or 882868 counting only the distinct ones).

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

Adding to 21020221020 its reverse (2012202012), we get a palindrome (23032423032).

The spelling of 21020221020 in words is "twenty-one billion, twenty million, two hundred twenty-one thousand, twenty".