21112021001 has 4 divisors (see below), whose sum is σ = 21157817604. Its totient is φ = 21066224400.

The previous prime is 21112020971. The next prime is 21112021033. The reversal of 21112021001 is 10012021112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3240341776 + 17871679225 = 56924^2 + 133685^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112021001 - 2¹⁰ = 21112019977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21112021061) 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, 22897610 + ... + 22898531.

It is an arithmetic number, because the mean of its divisors is an integer number (5289454401).

Almost surely, 2^21112021001 is an apocalyptic number.

It is an amenable number.

21112021001 is a deficient number, since it is larger than the sum of its proper divisors (45796603).

21112021001 is an equidigital number, since it uses as much as digits as its factorization.

21112021001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45796602.

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

Adding to 21112021001 its reverse (10012021112), we get a palindrome (31124042113).

The spelling of 21112021001 in words is "twenty-one billion, one hundred twelve million, twenty-one thousand, one".