21211012112221 has 16 divisors (see below), whose sum is σ = 21949401988800. Its totient is φ = 20483789977728.

The previous prime is 21211012112201. The next prime is 21211012112309. The reversal of 21211012112221 is 12221121011212.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21211012112221 - 2¹⁹ = 21211011587933 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 (21211012112201) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 71788690 + ... + 72083548.

It is an arithmetic number, because the mean of its divisors is an integer number (1371837624300).

Almost surely, 2^{21211012112221} is an apocalyptic number.

It is an amenable number.

21211012112221 is a deficient number, since it is larger than the sum of its proper divisors (738389876579).

21211012112221 is a wasteful number, since it uses less digits than its factorization.

21211012112221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313788.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21211012112221 its reverse (12221121011212), we get a palindrome (33432133123433).

The spelling of 21211012112221 in words is "twenty-one trillion, two hundred eleven billion, twelve million, one hundred twelve thousand, two hundred twenty-one".