21324135216161 has 4 divisors (see below), whose sum is σ = 21324150471492. Its totient is φ = 21324119960832.

The previous prime is 21324135216151. The next prime is 21324135216191. The reversal of 21324135216161 is 16161253142312.

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 4685233411600 + 16638901804561 = 2164540^2 + 4079081^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21324135216161 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21324135216121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5292680 + ... + 8405993.

It is an arithmetic number, because the mean of its divisors is an integer number (5331037617873).

Almost surely, 2^{21324135216161} is an apocalyptic number.

It is an amenable number.

21324135216161 is a deficient number, since it is larger than the sum of its proper divisors (15255331).

21324135216161 is a wasteful number, since it uses less digits than its factorization.

21324135216161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15255330.

The product of its digits is 51840, while the sum is 38.

Adding to 21324135216161 its reverse (16161253142312), we get a palindrome (37485388358473).

The spelling of 21324135216161 in words is "twenty-one trillion, three hundred twenty-four billion, one hundred thirty-five million, two hundred sixteen thousand, one hundred sixty-one".