21011221100201 has 4 divisors (see below), whose sum is σ = 21013033517652. Its totient is φ = 21009408682752.

The previous prime is 21011221100183. The next prime is 21011221100231. The reversal of 21011221100201 is 10200112211012.

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 13308925459600 + 7702295640601 = 3648140^2 + 2775301^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21011221100201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21011221100231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 906191336 + ... + 906214521.

It is an arithmetic number, because the mean of its divisors is an integer number (5253258379413).

Almost surely, 2^{21011221100201} is an apocalyptic number.

It is an amenable number.

21011221100201 is a deficient number, since it is larger than the sum of its proper divisors (1812417451).

21011221100201 is a wasteful number, since it uses less digits than its factorization.

21011221100201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1812417450.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21011221100201 its reverse (10200112211012), we get a palindrome (31211333311213).

The spelling of 21011221100201 in words is "twenty-one trillion, eleven billion, two hundred twenty-one million, one hundred thousand, two hundred one".