21201122001 has 4 divisors (see below), whose sum is σ = 28268162672. Its totient is φ = 14134081332.

The previous prime is 21201121973. The next prime is 21201122023. The reversal of 21201122001 is 10022110212.

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 21201122001 - 2⁵ = 21201121969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21201122801) 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, 3533520331 + ... + 3533520336.

It is an arithmetic number, because the mean of its divisors is an integer number (7067040668).

Almost surely, 2^21201122001 is an apocalyptic number.

It is an amenable number.

21201122001 is a deficient number, since it is larger than the sum of its proper divisors (7067040671).

21201122001 is an equidigital number, since it uses as much as digits as its factorization.

21201122001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7067040670.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21201122001 its reverse (10022110212), we get a palindrome (31223232213).

The spelling of 21201122001 in words is "twenty-one billion, two hundred one million, one hundred twenty-two thousand, one".