21121116511 has 8 divisors (see below), whose sum is σ = 23043493584. Its totient is φ = 19199118720.

The previous prime is 21121116487. The next prime is 21121116529. The reversal of 21121116511 is 11561112112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21121116511 - 2¹⁷ = 21120985439 is a prime.

It is a super-2 number, since 2×21121116511² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121110511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28615 + ... + 207511.

It is an arithmetic number, because the mean of its divisors is an integer number (2880436698).

Almost surely, 2^21121116511 is an apocalyptic number.

21121116511 is a deficient number, since it is larger than the sum of its proper divisors (1922377073).

21121116511 is a wasteful number, since it uses less digits than its factorization.

21121116511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189641.

The product of its digits is 120, while the sum is 22.

Adding to 21121116511 its reverse (11561112112), we get a palindrome (32682228623).

It can be divided in two parts, 211211 and 16511, that added together give a palindrome (227722).

The spelling of 21121116511 in words is "twenty-one billion, one hundred twenty-one million, one hundred sixteen thousand, five hundred eleven".