21016085 has 4 divisors (see below), whose sum is σ = 25219308. Its totient is φ = 16812864.

The previous prime is 21016057. The next prime is 21016103. The reversal of 21016085 is 58061012.

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

It can be written as a sum of positive squares in 2 ways, for example, as 15437041 + 5579044 = 3929^2 + 2362^2 .

It is a cyclic number.

It is not a de Polignac number, because 21016085 - 2⁸ = 21015829 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21016085.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2101604 + ... + 2101613.

It is an arithmetic number, because the mean of its divisors is an integer number (6304827).

Almost surely, 2^21016085 is an apocalyptic number.

It is an amenable number.

21016085 is a deficient number, since it is larger than the sum of its proper divisors (4203223).

21016085 is an equidigital number, since it uses as much as digits as its factorization.

21016085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4203222.

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 21016085 is about 4584.3303764018. The cubic root of 21016085 is about 275.9628398126.

Adding to 21016085 its reverse (58061012), we get a palindrome (79077097).

The spelling of 21016085 in words is "twenty-one million, sixteen thousand, eighty-five".