21221212101020 has 24 divisors (see below), whose sum is σ = 44564865886800. Its totient is φ = 8488423797632.

The previous prime is 21221212100989. The next prime is 21221212101049. The reversal of 21221212101020 is 2010121212212.

It is a self number, because there is not a number n which added to its sum of digits gives 21221212101020.

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, 910550 + ... + 6578109.

It is an arithmetic number, because the mean of its divisors is an integer number (1856869411950).

Almost surely, 2^{21221212101020} is an apocalyptic number.

21221212101020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221212101020 is an abundant number, since it is smaller than the sum of its proper divisors (23343653785780).

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

21221212101020 is a wasteful number, since it uses less digits than its factorization.

21221212101020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7630357 (or 7630355 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21221212101020 its reverse (2010121212212), we get a palindrome (23231333313232).

The spelling of 21221212101020 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twelve million, one hundred one thousand, twenty".