21221200101020 has 24 divisors (see below), whose sum is σ = 44564643036144. Its totient is φ = 8488456645376.

The previous prime is 21221200100959. The next prime is 21221200101029. The reversal of 21221200101020 is 2010100212212.

It is a junction number, because it is equal to n+sod(n) for n = 21221200100986 and 21221200101004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221200101029) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7238687 + ... + 9738633.

It is an arithmetic number, because the mean of its divisors is an integer number (1856860126506).

Almost surely, 2^{21221200101020} is an apocalyptic number.

21221200101020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221200101020 is an abundant number, since it is smaller than the sum of its proper divisors (23343442935124).

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

21221200101020 is a wasteful number, since it uses less digits than its factorization.

21221200101020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2924389 (or 2924387 counting only the distinct ones).

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

Adding to 21221200101020 its reverse (2010100212212), we get a palindrome (23231300313232).

The spelling of 21221200101020 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred million, one hundred one thousand, twenty".