21316315 has 8 divisors (see below), whose sum is σ = 25781760. Its totient is φ = 16918272.

The previous prime is 21316307. The next prime is 21316319. The reversal of 21316315 is 51361312.

It is a happy number.

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 21316315 - 2³ = 21316307 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21316319) 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, 16150 + ... + 17419.

It is an arithmetic number, because the mean of its divisors is an integer number (3222720).

Almost surely, 2^21316315 is an apocalyptic number.

21316315 is a deficient number, since it is larger than the sum of its proper divisors (4465445).

21316315 is a wasteful number, since it uses less digits than its factorization.

21316315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33701.

The product of its digits is 540, while the sum is 22.

The square root of 21316315 is about 4616.9594973316. The cubic root of 21316315 is about 277.2707410378.

Adding to 21316315 its reverse (51361312), we get a palindrome (72677627).

The spelling of 21316315 in words is "twenty-one million, three hundred sixteen thousand, three hundred fifteen".