65121613 has 4 divisors (see below), whose sum is σ = 65267100. Its totient is φ = 64976128.

The previous prime is 65121599. The next prime is 65121631. The reversal of 65121613 is 31612156.

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 46485124 + 18636489 = 6818^2 + 4317^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-65121613 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 (65121673) 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, 72070 + ... + 72967.

It is an arithmetic number, because the mean of its divisors is an integer number (16316775).

Almost surely, 2^65121613 is an apocalyptic number.

It is an amenable number.

65121613 is a deficient number, since it is larger than the sum of its proper divisors (145487).

65121613 is a wasteful number, since it uses less digits than its factorization.

65121613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145486.

The product of its digits is 1080, while the sum is 25.

The square root of 65121613 is about 8069.7963419159. The cubic root of 65121613 is about 402.3231747755.

Adding to 65121613 its reverse (31612156), we get a palindrome (96733769).

The spelling of 65121613 in words is "sixty-five million, one hundred twenty-one thousand, six hundred thirteen".