21002111200221 has 16 divisors (see below), whose sum is σ = 28762349571648. Its totient is φ = 13621711248000.

The previous prime is 21002111200211. The next prime is 21002111200267. The reversal of 21002111200221 is 12200211120012.

It is not a de Polignac number, because 21002111200221 - 2¹⁸ = 21002110938077 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21002111200221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002111200211) 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, 7699920 + ... + 10064441.

It is an arithmetic number, because the mean of its divisors is an integer number (1797646848228).

Almost surely, 2^{21002111200221} is an apocalyptic number.

It is an amenable number.

21002111200221 is a deficient number, since it is larger than the sum of its proper divisors (7760238371427).

21002111200221 is a wasteful number, since it uses less digits than its factorization.

21002111200221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17775052.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21002111200221 its reverse (12200211120012), we get a palindrome (33202322320233).

The spelling of 21002111200221 in words is "twenty-one trillion, two billion, one hundred eleven million, two hundred thousand, two hundred twenty-one".