72191191 has 4 divisors (see below), whose sum is σ = 72718272. Its totient is φ = 71664112.

The previous prime is 72191177. The next prime is 72191257. The reversal of 72191191 is 19119127.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19119127 = 59 ⋅324053.

It is a cyclic number.

It is not a de Polignac number, because 72191191 - 2¹⁵ = 72158423 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 (72191101) 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, 263335 + ... + 263608.

It is an arithmetic number, because the mean of its divisors is an integer number (18179568).

Almost surely, 2^72191191 is an apocalyptic number.

72191191 is a deficient number, since it is larger than the sum of its proper divisors (527081).

72191191 is a wasteful number, since it uses less digits than its factorization.

72191191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 527080.

The product of its digits is 1134, while the sum is 31.

The square root of 72191191 is about 8496.5399428238. The cubic root of 72191191 is about 416.3846736927.

The spelling of 72191191 in words is "seventy-two million, one hundred ninety-one thousand, one hundred ninety-one".