21516368 has 20 divisors (see below), whose sum is σ = 41807220. Its totient is φ = 10727424.

The previous prime is 21516359. The next prime is 21516403. The reversal of 21516368 is 86361512.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 2050624 + 19465744 = 1432^2 + 4412^2 .

It is a super-2 number, since 2×21516368² = 925908183822848, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4496 + ... + 7952.

It is an arithmetic number, because the mean of its divisors is an integer number (2090361).

Almost surely, 2^21516368 is an apocalyptic number.

It is an amenable number.

21516368 is a deficient number, since it is larger than the sum of its proper divisors (20290852).

21516368 is a wasteful number, since it uses less digits than its factorization.

21516368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3854 (or 3848 counting only the distinct ones).

The product of its digits is 8640, while the sum is 32.

The square root of 21516368 is about 4638.5739187815. The cubic root of 21516368 is about 278.1354342422.

The spelling of 21516368 in words is "twenty-one million, five hundred sixteen thousand, three hundred sixty-eight".