21616040306165 has 16 divisors (see below), whose sum is σ = 26498680595712. Its totient is φ = 16920086685504.

The previous prime is 21616040306129. The next prime is 21616040306167. The reversal of 21616040306165 is 56160304061612.

It is a cyclic number.

It is not a de Polignac number, because 21616040306165 - 2²² = 21616036111861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21616040306167) 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, 12250439 + ... + 13903428.

It is an arithmetic number, because the mean of its divisors is an integer number (1656167537232).

Almost surely, 2^{21616040306165} is an apocalyptic number.

It is an amenable number.

21616040306165 is a deficient number, since it is larger than the sum of its proper divisors (4882640289547).

21616040306165 is a wasteful number, since it uses less digits than its factorization.

21616040306165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26157436.

The product of its (nonzero) digits is 155520, while the sum is 41.

Adding to 21616040306165 its reverse (56160304061612), we get a palindrome (77776344367777).

The spelling of 21616040306165 in words is "twenty-one trillion, six hundred sixteen billion, forty million, three hundred six thousand, one hundred sixty-five".