72717121 has 4 divisors (see below), whose sum is σ = 72881712. Its totient is φ = 72552532.

The previous prime is 72717119. The next prime is 72717137. The reversal of 72717121 is 12171727.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 72717121 - 2¹ = 72717119 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 72717121.

It is not an unprimeable number, because it can be changed into a prime (72727121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81631 + ... + 82516.

It is an arithmetic number, because the mean of its divisors is an integer number (18220428).

Almost surely, 2^72717121 is an apocalyptic number.

It is an amenable number.

72717121 is a deficient number, since it is larger than the sum of its proper divisors (164591).

72717121 is a wasteful number, since it uses less digits than its factorization.

72717121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164590.

The product of its digits is 1372, while the sum is 28.

The square root of 72717121 is about 8527.4334356827. The cubic root of 72717121 is about 417.3933818849.

Adding to 72717121 its reverse (12171727), we get a palindrome (84888848).

The spelling of 72717121 in words is "seventy-two million, seven hundred seventeen thousand, one hundred twenty-one".