72728191 has 4 divisors (see below), whose sum is σ = 72748872. Its totient is φ = 72707512.

The previous prime is 72728177. The next prime is 72728203. The reversal of 72728191 is 19182727.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 72728191 - 2⁷ = 72728063 is a prime.

It is a super-2 number, since 2×72728191² = 10578779532264962, which contains 22 as substring.

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 72728191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72728101) 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, 3601 + ... + 12586.

It is an arithmetic number, because the mean of its divisors is an integer number (18187218).

Almost surely, 2^72728191 is an apocalyptic number.

72728191 is a deficient number, since it is larger than the sum of its proper divisors (20681).

72728191 is a wasteful number, since it uses less digits than its factorization.

72728191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20680.

The product of its digits is 14112, while the sum is 37.

The square root of 72728191 is about 8528.0824925654. The cubic root of 72728191 is about 417.4145612634.

The spelling of 72728191 in words is "seventy-two million, seven hundred twenty-eight thousand, one hundred ninety-one".