21516063 has 8 divisors (see below), whose sum is σ = 29935488. Its totient is φ = 13720344.

The previous prime is 21516041. The next prime is 21516071. The reversal of 21516063 is 36061512.

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

It is not a de Polignac number, because 21516063 - 2⁹ = 21515551 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21516563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 155845 + ... + 155982.

It is an arithmetic number, because the mean of its divisors is an integer number (3741936).

Almost surely, 2^21516063 is an apocalyptic number.

21516063 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21516063 is a deficient number, since it is larger than the sum of its proper divisors (8419425).

21516063 is a wasteful number, since it uses less digits than its factorization.

21516063 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311853.

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 21516063 is about 4638.5410421813. The cubic root of 21516063 is about 278.1341200224.

Adding to 21516063 its reverse (36061512), we get a palindrome (57577575).

The spelling of 21516063 in words is "twenty-one million, five hundred sixteen thousand, sixty-three".