21001012211111 has 4 divisors (see below), whose sum is σ = 21266847808800. Its totient is φ = 20735176613424.

The previous prime is 21001012211033. The next prime is 21001012211197. The reversal of 21001012211111 is 11111221010012.

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

It is a cyclic number.

It is not a de Polignac number, because 21001012211111 - 2¹⁴ = 21001012194727 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001012271111) 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, 132917798726 + ... + 132917798883.

It is an arithmetic number, because the mean of its divisors is an integer number (5316711952200).

Almost surely, 2^{21001012211111} is an apocalyptic number.

21001012211111 is a deficient number, since it is larger than the sum of its proper divisors (265835597689).

21001012211111 is an equidigital number, since it uses as much as digits as its factorization.

21001012211111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265835597688.

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 21001012211111 its reverse (11111221010012), we get a palindrome (32112233221123).

The spelling of 21001012211111 in words is "twenty-one trillion, one billion, twelve million, two hundred eleven thousand, one hundred eleven".