21001233111 has 16 divisors (see below), whose sum is σ = 28048312320. Its totient is φ = 13977512640.

The previous prime is 21001233091. The next prime is 21001233133. The reversal of 21001233111 is 11133210012.

It is a happy number.

It is not a de Polignac number, because 21001233111 - 2¹¹ = 21001231063 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001233151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6542875 + ... + 6546083.

It is an arithmetic number, because the mean of its divisors is an integer number (1753019520).

Almost surely, 2^21001233111 is an apocalyptic number.

21001233111 is a deficient number, since it is larger than the sum of its proper divisors (7047079209).

21001233111 is a wasteful number, since it uses less digits than its factorization.

21001233111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6166.

The product of its (nonzero) digits is 36, while the sum is 15.

Adding to 21001233111 its reverse (11133210012), we get a palindrome (32134443123).

The spelling of 21001233111 in words is "twenty-one billion, one million, two hundred thirty-three thousand, one hundred eleven".