21001111201201 has 4 divisors (see below), whose sum is σ = 21017303269732. Its totient is φ = 20984919132672.

The previous prime is 21001111201117. The next prime is 21001111201219. The reversal of 21001111201201 is 10210211110012.

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 19217711207601 + 1783399993600 = 4383801^2 + 1335440^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001111201201 - 2³³ = 20992521266609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001111201241) 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, 8096032320 + ... + 8096034913.

It is an arithmetic number, because the mean of its divisors is an integer number (5254325817433).

Almost surely, 2^{21001111201201} is an apocalyptic number.

It is an amenable number.

21001111201201 is a deficient number, since it is larger than the sum of its proper divisors (16192068531).

21001111201201 is a wasteful number, since it uses less digits than its factorization.

21001111201201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16192068530.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21001111201201 its reverse (10210211110012), we get a palindrome (31211322311213).

The spelling of 21001111201201 in words is "twenty-one trillion, one billion, one hundred eleven million, two hundred one thousand, two hundred one".