21000212112111 has 16 divisors (see below), whose sum is σ = 28106463823200. Its totient is φ = 13947058649088.

The previous prime is 21000212112107. The next prime is 21000212112169. The reversal of 21000212112111 is 11121121200012.

It is a happy number.

It is not a de Polignac number, because 21000212112111 - 2² = 21000212112107 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000212114111) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9963195 + ... + 11885523.

It is an arithmetic number, because the mean of its divisors is an integer number (1756653988950).

Almost surely, 2^{21000212112111} is an apocalyptic number.

21000212112111 is a deficient number, since it is larger than the sum of its proper divisors (7106251711089).

21000212112111 is a wasteful number, since it uses less digits than its factorization.

21000212112111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1936138.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21000212112111 its reverse (11121121200012), we get a palindrome (32121333312123).

The spelling of 21000212112111 in words is "twenty-one trillion, two hundred twelve million, one hundred twelve thousand, one hundred eleven".