21021212102020 has 48 divisors (see below), whose sum is σ = 47552802394608. Its totient is φ = 7759633789440.

The previous prime is 21021212101993. The next prime is 21021212102057. The reversal of 21021212102020 is 2020121212012.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 4424762734144 + 16596449367876 = 2103512^2 + 4073874^2 .

It is a super-2 number, since 2×21021212102020² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21021212101985 and 21021212102003.

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, 9659451 + ... + 11633890.

It is an arithmetic number, because the mean of its divisors is an integer number (990683383221).

Almost surely, 2^{21021212102020} is an apocalyptic number.

21021212102020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021212102020 is an abundant number, since it is smaller than the sum of its proper divisors (26531590292588).

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

21021212102020 is a wasteful number, since it uses less digits than its factorization.

21021212102020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21297160 (or 21297158 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21021212102020 its reverse (2020121212012), we get a palindrome (23041333314032).

The spelling of 21021212102020 in words is "twenty-one trillion, twenty-one billion, two hundred twelve million, one hundred two thousand, twenty".