21117109 has 8 divisors (see below), whose sum is σ = 23016672. Its totient is φ = 19256880.

The previous prime is 21117097. The next prime is 21117137. The reversal of 21117109 is 90171112.

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 21117109 - 2⁹ = 21116597 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21117109.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21117209) 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 7 ways as a sum of consecutive naturals, for example, 8707 + ... + 10864.

It is an arithmetic number, because the mean of its divisors is an integer number (2877084).

Almost surely, 2^21117109 is an apocalyptic number.

It is an amenable number.

21117109 is a deficient number, since it is larger than the sum of its proper divisors (1899563).

21117109 is a wasteful number, since it uses less digits than its factorization.

21117109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19667.

The product of its (nonzero) digits is 126, while the sum is 22.

The square root of 21117109 is about 4595.3355699013. The cubic root of 21117109 is about 276.4043162300.

It can be divided in two parts, 2 and 1117109, that added together give a palindrome (1117111).

The spelling of 21117109 in words is "twenty-one million, one hundred seventeen thousand, one hundred nine".