21111109 has 8 divisors (see below), whose sum is σ = 22320000. Its totient is φ = 19912032.

The previous prime is 21111073. The next prime is 21111113. The reversal of 21111109 is 90111112.

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 21111109 - 2⁷ = 21110981 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111092 and 21111101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111149) 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, 2217 + ... + 6865.

It is an arithmetic number, because the mean of its divisors is an integer number (2790000).

Almost surely, 2^21111109 is an apocalyptic number.

It is an amenable number.

21111109 is a deficient number, since it is larger than the sum of its proper divisors (1208891).

21111109 is a wasteful number, since it uses less digits than its factorization.

21111109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4907.

The product of its (nonzero) digits is 18, while the sum is 16.

The square root of 21111109 is about 4594.6826876293. The cubic root of 21111109 is about 276.3781355157.

It can be divided in two parts, 2 and 1111109, that added together give a palindrome (1111111).

The spelling of 21111109 in words is "twenty-one million, one hundred eleven thousand, one hundred nine".