21121110111211 has 4 divisors (see below), whose sum is σ = 23041211030424. Its totient is φ = 19201009192000.

The previous prime is 21121110111203. The next prime is 21121110111217. The reversal of 21121110111211 is 11211101112112.

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 21121110111211 - 2³ = 21121110111203 is a prime.

It is a super-2 number, since 2×21121110111211² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21121110111217) 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, 960050459590 + ... + 960050459611.

It is an arithmetic number, because the mean of its divisors is an integer number (5760302757606).

Almost surely, 2^{21121110111211} is an apocalyptic number.

21121110111211 is a deficient number, since it is larger than the sum of its proper divisors (1920100919213).

21121110111211 is a wasteful number, since it uses less digits than its factorization.

21121110111211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1920100919212.

The product of its (nonzero) digits is 8, while the sum is 16.

Adding to 21121110111211 its reverse (11211101112112), we get a palindrome (32332211223323).

It can be divided in two parts, 2 and 1121110111211, that multiplied together give a palindrome (2242220222422).

The spelling of 21121110111211 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred ten million, one hundred eleven thousand, two hundred eleven".