21216083 has 4 divisors (see below), whose sum is σ = 24246960. Its totient is φ = 18185208.

The previous prime is 21216073. The next prime is 21216127. The reversal of 21216083 is 38061212.

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

It is a cyclic number.

It is not a de Polignac number, because 21216083 - 2⁸ = 21215827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21216053) 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, 1515428 + ... + 1515441.

It is an arithmetic number, because the mean of its divisors is an integer number (6061740).

Almost surely, 2^21216083 is an apocalyptic number.

21216083 is a deficient number, since it is larger than the sum of its proper divisors (3030877).

21216083 is an equidigital number, since it uses as much as digits as its factorization.

21216083 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3030876.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 21216083 is about 4606.0919443711. The cubic root of 21216083 is about 276.8354707668.

Adding to 21216083 its reverse (38061212), we get a palindrome (59277295).

The spelling of 21216083 in words is "twenty-one million, two hundred sixteen thousand, eighty-three".