21616063 has 4 divisors (see below), whose sum is σ = 24704080. Its totient is φ = 18528048.

The previous prime is 21616051. The next prime is 21616069. The reversal of 21616063 is 36061612.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21616063 - 2⁵ = 21616031 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21616069) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1543998 + ... + 1544011.

It is an arithmetic number, because the mean of its divisors is an integer number (6176020).

Almost surely, 2^21616063 is an apocalyptic number.

21616063 is a deficient number, since it is larger than the sum of its proper divisors (3088017).

21616063 is an equidigital number, since it uses as much as digits as its factorization.

21616063 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3088016.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 21616063 is about 4649.3077979415. The cubic root of 21616063 is about 278.5643479494.

Adding to 21616063 its reverse (36061612), we get a palindrome (57677675).

The spelling of 21616063 in words is "twenty-one million, six hundred sixteen thousand, sixty-three".