21000011221020 has 48 divisors (see below), whose sum is σ = 63323110761120. Its totient is φ = 5169233531136.

The previous prime is 21000011221009. The next prime is 21000011221027. The reversal of 21000011221020 is 2012211000012.

It is a super-2 number, since 2×21000011221020² (a number of 27 digits) contains 22 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 = 21000011220987 and 21000011221005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000011221027) by changing a digit.

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, 13461544875 + ... + 13461546434.

It is an arithmetic number, because the mean of its divisors is an integer number (1319231474190).

Almost surely, 2^{21000011221020} is an apocalyptic number.

21000011221020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000011221020 is an abundant number, since it is smaller than the sum of its proper divisors (42323099540100).

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

21000011221020 is a wasteful number, since it uses less digits than its factorization.

21000011221020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26923091334 (or 26923091332 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21000011221020 its reverse (2012211000012), we get a palindrome (23012222221032).

The spelling of 21000011221020 in words is "twenty-one trillion, eleven million, two hundred twenty-one thousand, twenty".