72145771 has 4 divisors (see below), whose sum is σ = 72549000. Its totient is φ = 71742544.

The previous prime is 72145757. The next prime is 72145781. The reversal of 72145771 is 17754127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17754127 = 151 ⋅117577.

It is a cyclic number.

It is not a de Polignac number, because 72145771 - 2¹⁵ = 72113003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72145721) 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, 201346 + ... + 201703.

It is an arithmetic number, because the mean of its divisors is an integer number (18137250).

Almost surely, 2^72145771 is an apocalyptic number.

72145771 is a deficient number, since it is larger than the sum of its proper divisors (403229).

72145771 is a wasteful number, since it uses less digits than its factorization.

72145771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 403228.

The product of its digits is 13720, while the sum is 34.

The square root of 72145771 is about 8493.8666695446. The cubic root of 72145771 is about 416.2973308130.

Adding to 72145771 its reverse (17754127), we get a palindrome (89899898).

The spelling of 72145771 in words is "seventy-two million, one hundred forty-five thousand, seven hundred seventy-one".