21211121012111 has 4 divisors (see below), whose sum is σ = 21570631537800. Its totient is φ = 20851610486424.

The previous prime is 21211121012093. The next prime is 21211121012113. The reversal of 21211121012111 is 11121012111212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21211121012111 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21211121012111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211121012113) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 179755262756 + ... + 179755262873.

It is an arithmetic number, because the mean of its divisors is an integer number (5392657884450).

Almost surely, 2^{21211121012111} is an apocalyptic number.

21211121012111 is a deficient number, since it is larger than the sum of its proper divisors (359510525689).

21211121012111 is an equidigital number, since it uses as much as digits as its factorization.

21211121012111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 359510525688.

The product of its (nonzero) digits is 16, while the sum is 17.

Adding to 21211121012111 its reverse (11121012111212), we get a palindrome (32332133123323).

It can be divided in two parts, 212 and 11121012111, that multiplied together give a palindrome (2357654567532).

The spelling of 21211121012111 in words is "twenty-one trillion, two hundred eleven billion, one hundred twenty-one million, twelve thousand, one hundred eleven".