21304315 has 16 divisors (see below), whose sum is σ = 27200448. Its totient is φ = 15963136.

The previous prime is 21304291. The next prime is 21304319. The reversal of 21304315 is 51340312.

It is a de Polignac number, because none of the positive numbers 2^k-21304315 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21304292 and 21304301.

It is not an unprimeable number, because it can be changed into a prime (21304319) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21879 + ... + 22831.

It is an arithmetic number, because the mean of its divisors is an integer number (1700028).

Almost surely, 2^21304315 is an apocalyptic number.

21304315 is a deficient number, since it is larger than the sum of its proper divisors (5896133).

21304315 is a wasteful number, since it uses less digits than its factorization.

21304315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1238.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21304315 is about 4615.6597578244. The cubic root of 21304315 is about 277.2187015015.

Adding to 21304315 its reverse (51340312), we get a palindrome (72644627).

The spelling of 21304315 in words is "twenty-one million, three hundred four thousand, three hundred fifteen".