21162065 has 4 divisors (see below), whose sum is σ = 25394484. Its totient is φ = 16929648.

The previous prime is 21162041. The next prime is 21162107. The reversal of 21162065 is 56026112.

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 14776336 + 6385729 = 3844^2 + 2527^2 .

It is a cyclic number.

It is not a de Polignac number, because 21162065 - 2¹⁴ = 21145681 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21162065.

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, 2116202 + ... + 2116211.

It is an arithmetic number, because the mean of its divisors is an integer number (6348621).

Almost surely, 2^21162065 is an apocalyptic number.

It is an amenable number.

21162065 is a deficient number, since it is larger than the sum of its proper divisors (4232419).

21162065 is an equidigital number, since it uses as much as digits as its factorization.

21162065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4232418.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 21162065 is about 4600.2244510458. The cubic root of 21162065 is about 276.6003219896.

Adding to 21162065 its reverse (56026112), we get a palindrome (77188177).

The spelling of 21162065 in words is "twenty-one million, one hundred sixty-two thousand, sixty-five".