21002111222201 has 4 divisors (see below), whose sum is σ = 21013930082292. Its totient is φ = 20990292362112.

The previous prime is 21002111222123. The next prime is 21002111222221. The reversal of 21002111222201 is 10222211120012.

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 11769537816976 + 9232573405225 = 3430676^2 + 3038515^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002111222201 - 2¹⁸ = 21002110960057 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21002111222201.

It is not an unprimeable number, because it can be changed into a prime (21002111222221) 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, 5909427380 + ... + 5909430933.

It is an arithmetic number, because the mean of its divisors is an integer number (5253482520573).

Almost surely, 2^{21002111222201} is an apocalyptic number.

It is an amenable number.

21002111222201 is a deficient number, since it is larger than the sum of its proper divisors (11818860091).

21002111222201 is a wasteful number, since it uses less digits than its factorization.

21002111222201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11818860090.

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

Adding to 21002111222201 its reverse (10222211120012), we get a palindrome (31224322342213).

The spelling of 21002111222201 in words is "twenty-one trillion, two billion, one hundred eleven million, two hundred twenty-two thousand, two hundred one".