21111107 has 4 divisors (see below), whose sum is σ = 21146160. Its totient is φ = 21076056.

The previous prime is 21111073. The next prime is 21111113. The reversal of 21111107 is 70111112.

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 21111107 - 2¹⁸ = 20848963 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111091 and 21111100.

It is not an unprimeable number, because it can be changed into a prime (21111157) 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, 16607 + ... + 17832.

It is an arithmetic number, because the mean of its divisors is an integer number (5286540).

Almost surely, 2^21111107 is an apocalyptic number.

21111107 is a deficient number, since it is larger than the sum of its proper divisors (35053).

21111107 is an equidigital number, since it uses as much as digits as its factorization.

21111107 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35052.

The product of its (nonzero) digits is 14, while the sum is 14.

The square root of 21111107 is about 4594.6824699864. The cubic root of 21111107 is about 276.3781267880.

Adding to 21111107 its reverse (70111112), we get a palindrome (91222219).

The spelling of 21111107 in words is "twenty-one million, one hundred eleven thousand, one hundred seven".