21221020202020 has 48 divisors (see below), whose sum is σ = 45016431925248. Its totient is φ = 8402559459840.

The previous prime is 21221020201999. The next prime is 21221020202101. The reversal of 21221020202020 is 2020202012212.

It is a super-2 number, since 2×21221020202020² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21221020201985 and 21221020202003.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8304501 + ... + 10554940.

It is an arithmetic number, because the mean of its divisors is an integer number (937842331776).

Almost surely, 2^{21221020202020} is an apocalyptic number.

21221020202020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221020202020 is an abundant number, since it is smaller than the sum of its proper divisors (23795411723228).

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

21221020202020 is a wasteful number, since it uses less digits than its factorization.

21221020202020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18860020 (or 18860018 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 21221020202020 its reverse (2020202012212), we get a palindrome (23241222214232).

The spelling of 21221020202020 in words is "twenty-one trillion, two hundred twenty-one billion, twenty million, two hundred two thousand, twenty".