21001120001 has 4 divisors (see below), whose sum is σ = 21129961392. Its totient is φ = 20872278612.

The previous prime is 21001119967. The next prime is 21001120003. The reversal of 21001120001 is 10002110012.

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 a de Polignac number, because none of the positive numbers 2^k-21001120001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001120003) 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, 64420451 + ... + 64420776.

It is an arithmetic number, because the mean of its divisors is an integer number (5282490348).

Almost surely, 2^21001120001 is an apocalyptic number.

It is an amenable number.

21001120001 is a deficient number, since it is larger than the sum of its proper divisors (128841391).

21001120001 is a wasteful number, since it uses less digits than its factorization.

21001120001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128841390.

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 21001120001 its reverse (10002110012), we get a palindrome (31003230013).

The spelling of 21001120001 in words is "twenty-one billion, one million, one hundred twenty thousand, one".