21236109 has 8 divisors (see below), whose sum is σ = 28973472. Its totient is φ = 13828080.

The previous prime is 21236101. The next prime is 21236123. The reversal of 21236109 is 90163212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21236109 - 2³ = 21236101 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21236101) 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, 82182 + ... + 82439.

It is an arithmetic number, because the mean of its divisors is an integer number (3621684).

Almost surely, 2^21236109 is an apocalyptic number.

It is an amenable number.

21236109 is a deficient number, since it is larger than the sum of its proper divisors (7737363).

21236109 is a wasteful number, since it uses less digits than its factorization.

21236109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164667.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 21236109 is about 4608.2652918425. The cubic root of 21236109 is about 276.9225456483.

The spelling of 21236109 in words is "twenty-one million, two hundred thirty-six thousand, one hundred nine".