21111065 has 16 divisors (see below), whose sum is σ = 26136000. Its totient is φ = 16360512.

The previous prime is 21111061. The next prime is 21111073. The reversal of 21111065 is 56011112.

It is a cyclic number.

It is not a de Polignac number, because 21111065 - 2² = 21111061 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21111061) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31706 + ... + 32364.

It is an arithmetic number, because the mean of its divisors is an integer number (1633500).

Almost surely, 2^21111065 is an apocalyptic number.

It is an amenable number.

21111065 is a deficient number, since it is larger than the sum of its proper divisors (5024935).

21111065 is a wasteful number, since it uses less digits than its factorization.

21111065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 856.

The product of its (nonzero) digits is 60, while the sum is 17.

The square root of 21111065 is about 4594.6778994833. The cubic root of 21111065 is about 276.3779435055.

Adding to 21111065 its reverse (56011112), we get a palindrome (77122177).

The spelling of 21111065 in words is "twenty-one million, one hundred eleven thousand, sixty-five".