21010212312221 has 4 divisors (see below), whose sum is σ = 22920231613344. Its totient is φ = 19100193011100.

The previous prime is 21010212312157. The next prime is 21010212312227. The reversal of 21010212312221 is 12221321201012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21010212312221 - 2⁶ = 21010212312157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21010212312193 and 21010212312202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010212312227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 955009650545 + ... + 955009650566.

It is an arithmetic number, because the mean of its divisors is an integer number (5730057903336).

Almost surely, 2^{21010212312221} is an apocalyptic number.

It is an amenable number.

21010212312221 is a deficient number, since it is larger than the sum of its proper divisors (1910019301123).

21010212312221 is a wasteful number, since it uses less digits than its factorization.

21010212312221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1910019301122.

The product of its (nonzero) digits is 192, while the sum is 20.

Adding to 21010212312221 its reverse (12221321201012), we get a palindrome (33231533513233).

The spelling of 21010212312221 in words is "twenty-one trillion, ten billion, two hundred twelve million, three hundred twelve thousand, two hundred twenty-one".