21338165 has 8 divisors (see below), whose sum is σ = 25631160. Its totient is φ = 17053632.

The previous prime is 21338153. The next prime is 21338183. The reversal of 21338165 is 56183312.

It can be written as a sum of positive squares in 4 ways, for example, as 1898884 + 19439281 = 1378^2 + 4409^2 .

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 21338165 - 2⁶ = 21338101 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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, 7067 + ... + 9623.

It is an arithmetic number, because the mean of its divisors is an integer number (3203895).

Almost surely, 2^21338165 is an apocalyptic number.

It is an amenable number.

21338165 is a deficient number, since it is larger than the sum of its proper divisors (4292995).

21338165 is a wasteful number, since it uses less digits than its factorization.

21338165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4231.

The product of its digits is 4320, while the sum is 29.

The square root of 21338165 is about 4619.3251671646. The cubic root of 21338165 is about 277.3654462257.

The spelling of 21338165 in words is "twenty-one million, three hundred thirty-eight thousand, one hundred sixty-five".