21200121001 has 4 divisors (see below), whose sum is σ = 21883995904. Its totient is φ = 20516246100.

The previous prime is 21200120989. The next prime is 21200121011. The reversal of 21200121001 is 10012100212.

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 a cyclic number.

It is not a de Polignac number, because 21200121001 - 2⁷ = 21200120873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21200121011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 341937405 + ... + 341937466.

It is an arithmetic number, because the mean of its divisors is an integer number (5470998976).

Almost surely, 2^21200121001 is an apocalyptic number.

It is an amenable number.

21200121001 is a deficient number, since it is larger than the sum of its proper divisors (683874903).

21200121001 is an equidigital number, since it uses as much as digits as its factorization.

21200121001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 683874902.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21200121001 its reverse (10012100212), we get a palindrome (31212221213).

The spelling of 21200121001 in words is "twenty-one billion, two hundred million, one hundred twenty-one thousand, one".