21012202121220 has 72 divisors (see below), whose sum is σ = 63738081703296. Its totient is φ = 5603159956032.

The previous prime is 21012202121203. The next prime is 21012202121353. The reversal of 21012202121220 is 2212120221012.

It is a happy number.

21012202121220 is a `hidden beast` number, since 2 + 10 + 1 + 220 + 212 + 1 + 220 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21012202121193 and 21012202121202.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10137159 + ... + 12032721.

It is an arithmetic number, because the mean of its divisors is an integer number (885251134768).

Almost surely, 2^{21012202121220} is an apocalyptic number.

21012202121220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21012202121220 is an abundant number, since it is smaller than the sum of its proper divisors (42725879582076).

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

21012202121220 is a wasteful number, since it uses less digits than its factorization.

21012202121220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1957161 (or 1957156 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21012202121220 its reverse (2212120221012), we get a palindrome (23224322342232).

The spelling of 21012202121220 in words is "twenty-one trillion, twelve billion, two hundred two million, one hundred twenty-one thousand, two hundred twenty".