21012221202020 has 24 divisors (see below), whose sum is σ = 44147804931384. Its totient is φ = 8400671260416.

The previous prime is 21012221202017. The next prime is 21012221202041. The reversal of 21012221202020 is 2020212221012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 672337681444 + 20339883520576 = 819962^2 + 4509976^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21012221202020.

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, 263535419 + ... + 263615138.

It is an arithmetic number, because the mean of its divisors is an integer number (1839491872141).

Almost surely, 2^{21012221202020} is an apocalyptic number.

21012221202020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21012221202020 is an abundant number, since it is smaller than the sum of its proper divisors (23135583729364).

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

21012221202020 is a wasteful number, since it uses less digits than its factorization.

21012221202020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 527152559 (or 527152557 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21012221202020 its reverse (2020212221012), we get a palindrome (23032433423032).

The spelling of 21012221202020 in words is "twenty-one trillion, twelve billion, two hundred twenty-one million, two hundred two thousand, twenty".