21201121001001 has 4 divisors (see below), whose sum is σ = 28268161334672. Its totient is φ = 14134080667332.

The previous prime is 21201121000999. The next prime is 21201121001009. The reversal of 21201121001001 is 10010012110212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21201121001001 - 2¹ = 21201121000999 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21201121001009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3533520166831 + ... + 3533520166836.

It is an arithmetic number, because the mean of its divisors is an integer number (7067040333668).

Almost surely, 2^{21201121001001} is an apocalyptic number.

It is an amenable number.

21201121001001 is a deficient number, since it is larger than the sum of its proper divisors (7067040333671).

21201121001001 is an equidigital number, since it uses as much as digits as its factorization.

21201121001001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7067040333670.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21201121001001 its reverse (10010012110212), we get a palindrome (31211133111213).

The spelling of 21201121001001 in words is "twenty-one trillion, two hundred one billion, one hundred twenty-one million, one thousand, one".