21030065 has 12 divisors (see below), whose sum is σ = 29356596. Its totient is φ = 14420448.

The previous prime is 21030049. The next prime is 21030083. The reversal of 21030065 is 56003012.

It can be written as a sum of positive squares in 2 ways, for example, as 14714896 + 6315169 = 3836^2 + 2513^2 .

It is not a de Polignac number, because 21030065 - 2⁴ = 21030049 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42674 + ... + 43163.

It is an arithmetic number, because the mean of its divisors is an integer number (2446383).

Almost surely, 2^21030065 is an apocalyptic number.

It is an amenable number.

21030065 is a deficient number, since it is larger than the sum of its proper divisors (8326531).

21030065 is an equidigital number, since it uses as much as digits as its factorization.

21030065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85856 (or 85849 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 21030065 is about 4585.8548821348. The cubic root of 21030065 is about 276.0240168486.

Adding to 21030065 its reverse (56003012), we get a palindrome (77033077).

The spelling of 21030065 in words is "twenty-one million, thirty thousand, sixty-five".