21002111122111 has 16 divisors (see below), whose sum is σ = 24480319846464. Its totient is φ = 17644074499584.

The previous prime is 21002111122099. The next prime is 21002111122123. The reversal of 21002111122111 is 11122111120012.

It is an interprime number because it is at equal distance from previous prime (21002111122099) and next prime (21002111122123).

It is a cyclic number.

It is not a de Polignac number, because 21002111122111 - 2¹⁷ = 21002110991039 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 (21002117122111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28608600 + ... + 29333533.

It is an arithmetic number, because the mean of its divisors is an integer number (1530019990404).

Almost surely, 2^{21002111122111} is an apocalyptic number.

21002111122111 is a deficient number, since it is larger than the sum of its proper divisors (3478208724353).

21002111122111 is an equidigital number, since it uses as much as digits as its factorization.

21002111122111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57943170.

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

Adding to 21002111122111 its reverse (11122111120012), we get a palindrome (32124222242123).

The spelling of 21002111122111 in words is "twenty-one trillion, two billion, one hundred eleven million, one hundred twenty-two thousand, one hundred eleven".