21516064 has 12 divisors (see below), whose sum is σ = 42359814. Its totient is φ = 10758016.

The previous prime is 21516041. The next prime is 21516071. The reversal of 21516064 is 46061512.

It can be written as a sum of positive squares in only one way, i.e., 17139600 + 4376464 = 4140^2 + 2092^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 336157 + ... + 336220.

Almost surely, 2^21516064 is an apocalyptic number.

It is an amenable number.

21516064 is a deficient number, since it is larger than the sum of its proper divisors (20843750).

21516064 is an equidigital number, since it uses as much as digits as its factorization.

21516064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 672387 (or 672379 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 21516064 is about 4638.5411499738. The cubic root of 21516064 is about 278.1341243314.

Adding to 21516064 its reverse (46061512), we get a palindrome (67577576).

The spelling of 21516064 in words is "twenty-one million, five hundred sixteen thousand, sixty-four".