21164109 has 16 divisors (see below), whose sum is σ = 28728000. Its totient is φ = 13857536.

The previous prime is 21164107. The next prime is 21164141. The reversal of 21164109 is 90146112.

It is a cyclic number.

It is not a de Polignac number, because 21164109 - 2¹ = 21164107 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21164107) 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 15 ways as a sum of consecutive naturals, for example, 50302 + ... + 50720.

It is an arithmetic number, because the mean of its divisors is an integer number (1795500).

Almost surely, 2^21164109 is an apocalyptic number.

It is an amenable number.

21164109 is a deficient number, since it is larger than the sum of its proper divisors (7563891).

21164109 is a wasteful number, since it uses less digits than its factorization.

21164109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 684.

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 21164109 is about 4600.4466087544. The cubic root of 21164109 is about 276.6092271202.

The spelling of 21164109 in words is "twenty-one million, one hundred sixty-four thousand, one hundred nine".