21202110221220 has 36 divisors (see below), whose sum is σ = 64313067671580. Its totient is φ = 5653896058944.

The previous prime is 21202110221153. The next prime is 21202110221269. The reversal of 21202110221220 is 2212201120212.

It is a happy number.

21202110221220 is a `hidden beast` number, since 2 + 12 + 0 + 211 + 0 + 221 + 220 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 14745185282916 + 6456924938304 = 3839946^2 + 2541048^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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 = 21202110221193 and 21202110221202.

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 11 ways as a sum of consecutive naturals, for example, 58894750435 + ... + 58894750794.

Almost surely, 2^{21202110221220} is an apocalyptic number.

21202110221220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21202110221220 is an abundant number, since it is smaller than the sum of its proper divisors (43110957450360).

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

21202110221220 is a wasteful number, since it uses less digits than its factorization.

21202110221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117789501244 (or 117789501239 counting only the distinct ones).

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

Adding to 21202110221220 its reverse (2212201120212), we get a palindrome (23414311341432).

The spelling of 21202110221220 in words is "twenty-one trillion, two hundred two billion, one hundred ten million, two hundred twenty-one thousand, two hundred twenty".