21212210020020 has 24 divisors (see below), whose sum is σ = 59394188056224. Its totient is φ = 5656589338656.

The previous prime is 21212210020019. The next prime is 21212210020031. The reversal of 21212210020020 is 2002001221212.

It is a Harshad number since it is a multiple of its sum of digits (15).

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, 176768416774 + ... + 176768416893.

It is an arithmetic number, because the mean of its divisors is an integer number (2474757835676).

Almost surely, 2^{21212210020020} is an apocalyptic number.

21212210020020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212210020020 is an abundant number, since it is smaller than the sum of its proper divisors (38181978036204).

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

21212210020020 is a wasteful number, since it uses less digits than its factorization.

21212210020020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 353536833679 (or 353536833677 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21212210020020 its reverse (2002001221212), we get a palindrome (23214211241232).

The spelling of 21212210020020 in words is "twenty-one trillion, two hundred twelve billion, two hundred ten million, twenty thousand, twenty".