221212210000021 has 4 divisors (see below), whose sum is σ = 222621204968332. Its totient is φ = 219803215031712.

The previous prime is 221212210000013. The next prime is 221212210000039. The reversal of 221212210000021 is 120000012212122.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 135895324482225 + 85316885517796 = 11657415^2 + 9236714^2 .

It is a cyclic number.

It is not a de Polignac number, because 221212210000021 - 2³ = 221212210000013 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 (221212210000051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 704497483920 + ... + 704497484233.

It is an arithmetic number, because the mean of its divisors is an integer number (55655301242083).

Almost surely, 2^{221212210000021} is an apocalyptic number.

It is an amenable number.

221212210000021 is a deficient number, since it is larger than the sum of its proper divisors (1408994968311).

221212210000021 is a wasteful number, since it uses less digits than its factorization.

221212210000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1408994968310.

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

Adding to 221212210000021 its reverse (120000012212122), we get a palindrome (341212222212143).

The spelling of 221212210000021 in words is "two hundred twenty-one trillion, two hundred twelve billion, two hundred ten million, twenty-one", and thus it is an aban number.