21111707 has 4 divisors (see below), whose sum is σ = 21121920. Its totient is φ = 21101496.

The previous prime is 21111703. The next prime is 21111743. The reversal of 21111707 is 70711112.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21111707 - 2² = 21111703 is a prime.

It is a super-3 number, since 3×21111707³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21111703) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 788 + ... + 6545.

It is an arithmetic number, because the mean of its divisors is an integer number (5280480).

Almost surely, 2^21111707 is an apocalyptic number.

21111707 is a deficient number, since it is larger than the sum of its proper divisors (10213).

21111707 is an equidigital number, since it uses as much as digits as its factorization.

21111707 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10212.

The product of its (nonzero) digits is 98, while the sum is 20.

The square root of 21111707 is about 4594.7477623913. The cubic root of 21111707 is about 276.3807450828.

Adding to 21111707 its reverse (70711112), we get a palindrome (91822819).

The spelling of 21111707 in words is "twenty-one million, one hundred eleven thousand, seven hundred seven".