72728591 has 4 divisors (see below), whose sum is σ = 78323112. Its totient is φ = 67134072.

The previous prime is 72728587. The next prime is 72728597. The reversal of 72728591 is 19582727.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19582727 = 3877 ⋅5051.

It is a cyclic number.

It is not a de Polignac number, because 72728591 - 2² = 72728587 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 (72728597) 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, 2797241 + ... + 2797266.

It is an arithmetic number, because the mean of its divisors is an integer number (19580778).

Almost surely, 2^72728591 is an apocalyptic number.

72728591 is a deficient number, since it is larger than the sum of its proper divisors (5594521).

72728591 is a wasteful number, since it uses less digits than its factorization.

72728591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5594520.

The product of its digits is 70560, while the sum is 41.

The square root of 72728591 is about 8528.1059444639. The cubic root of 72728591 is about 417.4153265124.

The spelling of 72728591 in words is "seventy-two million, seven hundred twenty-eight thousand, five hundred ninety-one".