221212102100021 has 32 divisors (see below), whose sum is σ = 230247783899136. Its totient is φ = 212304127896000.

The previous prime is 221212102099993. The next prime is 221212102100027. The reversal of 221212102100021 is 120001201212122.

It is a cyclic number.

It is not a de Polignac number, because 221212102100021 - 2¹⁰ = 221212102098997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221212102100027) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 1869186176 + ... + 1869304518.

It is an arithmetic number, because the mean of its divisors is an integer number (7195243246848).

Almost surely, 2^{221212102100021} is an apocalyptic number.

It is an amenable number.

221212102100021 is a deficient number, since it is larger than the sum of its proper divisors (9035681799115).

221212102100021 is a wasteful number, since it uses less digits than its factorization.

221212102100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119633.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 221212102100021 its reverse (120001201212122), we get a palindrome (341213303312143).

The spelling of 221212102100021 in words is "two hundred twenty-one trillion, two hundred twelve billion, one hundred two million, one hundred thousand, twenty-one".