72517121 has 4 divisors (see below), whose sum is σ = 76782852. Its totient is φ = 68251392.

The previous prime is 72517097. The next prime is 72517169. The reversal of 72517121 is 12171527.

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 34386496 + 38130625 = 5864^2 + 6175^2 .

It is a cyclic number.

It is not a de Polignac number, because 72517121 - 2¹⁰ = 72516097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72517171) 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, 2132840 + ... + 2132873.

It is an arithmetic number, because the mean of its divisors is an integer number (19195713).

Almost surely, 2^72517121 is an apocalyptic number.

It is an amenable number.

72517121 is a deficient number, since it is larger than the sum of its proper divisors (4265731).

72517121 is a wasteful number, since it uses less digits than its factorization.

72517121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4265730.

The product of its digits is 980, while the sum is 26.

The square root of 72517121 is about 8515.6985033525. The cubic root of 72517121 is about 417.0103665088.

Adding to 72517121 its reverse (12171527), we get a palindrome (84688648).

The spelling of 72517121 in words is "seventy-two million, five hundred seventeen thousand, one hundred twenty-one".