21021112001 has 4 divisors (see below), whose sum is σ = 21042761904. Its totient is φ = 20999462100.

The previous prime is 21021111959. The next prime is 21021112003. The reversal of 21021112001 is 10021112012.

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 21021112001 - 2¹⁰ = 21021110977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21021112003) 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, 10823495 + ... + 10825436.

It is an arithmetic number, because the mean of its divisors is an integer number (5260690476).

Almost surely, 2^21021112001 is an apocalyptic number.

It is an amenable number.

21021112001 is a deficient number, since it is larger than the sum of its proper divisors (21649903).

21021112001 is an equidigital number, since it uses as much as digits as its factorization.

21021112001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21649902.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21021112001 its sum of digits (11), we get a palindrome (21021112012).

Adding to 21021112001 its reverse (10021112012), we get a palindrome (31042224013).

The spelling of 21021112001 in words is "twenty-one billion, twenty-one million, one hundred twelve thousand, one".