21201011212111 has 4 divisors (see below), whose sum is σ = 21201264481552. Its totient is φ = 21200757942672.

The previous prime is 21201011212109. The next prime is 21201011212123. The reversal of 21201011212111 is 11121211010212.

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 21201011212111 - 2¹ = 21201011212109 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 (21201011212181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 126509115 + ... + 126676588.

It is an arithmetic number, because the mean of its divisors is an integer number (5300316120388).

Almost surely, 2^{21201011212111} is an apocalyptic number.

21201011212111 is a deficient number, since it is larger than the sum of its proper divisors (253269441).

21201011212111 is an equidigital number, since it uses as much as digits as its factorization.

21201011212111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253269440.

The product of its (nonzero) digits is 16, while the sum is 16.

Adding to 21201011212111 its reverse (11121211010212), we get a palindrome (32322222222323).

The spelling of 21201011212111 in words is "twenty-one trillion, two hundred one billion, eleven million, two hundred twelve thousand, one hundred eleven".