21316165 has 8 divisors (see below), whose sum is σ = 27547128. Its totient is φ = 15741120.

The previous prime is 21316153. The next prime is 21316177. The reversal of 21316165 is 56161312.

It is an interprime number because it is at equal distance from previous prime (21316153) and next prime (21316177).

It can be written as a sum of positive squares in 4 ways, for example, as 1442401 + 19873764 = 1201^2 + 4458^2 .

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

It is not a de Polignac number, because 21316165 - 2⁵ = 21316133 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 163906 + ... + 164035.

It is an arithmetic number, because the mean of its divisors is an integer number (3443391).

Almost surely, 2^21316165 is an apocalyptic number.

It is an amenable number.

21316165 is a deficient number, since it is larger than the sum of its proper divisors (6230963).

21316165 is a wasteful number, since it uses less digits than its factorization.

21316165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 327959.

The product of its digits is 1080, while the sum is 25.

The square root of 21316165 is about 4616.9432528460. The cubic root of 21316165 is about 277.2700906641.

Adding to 21316165 its reverse (56161312), we get a palindrome (77477477).

The spelling of 21316165 in words is "twenty-one million, three hundred sixteen thousand, one hundred sixty-five".