21221001012020 has 24 divisors (see below), whose sum is σ = 44592871785000. Its totient is φ = 8482920469632.

The previous prime is 21221001011981. The next prime is 21221001012067. The reversal of 21221001012020 is 2021010012212.

It can be written as a sum of positive squares in 4 ways, for example, as 72370684324 + 21148630327696 = 269018^2 + 4598764^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21221001011986 and 21221001012004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 342464195 + ... + 342526154.

It is an arithmetic number, because the mean of its divisors is an integer number (1858036324375).

Almost surely, 2^{21221001012020} is an apocalyptic number.

21221001012020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221001012020 is an abundant number, since it is smaller than the sum of its proper divisors (23371870772980).

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

21221001012020 is a wasteful number, since it uses less digits than its factorization.

21221001012020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 684991907 (or 684991905 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21221001012020 its reverse (2021010012212), we get a palindrome (23242011024232).

The spelling of 21221001012020 in words is "twenty-one trillion, two hundred twenty-one billion, one million, twelve thousand, twenty".