72117643 has 4 divisors (see below), whose sum is σ = 77665168. Its totient is φ = 66570120.

The previous prime is 72117641. The next prime is 72117653. The reversal of 72117643 is 34671127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34671127 = 127 ⋅273001.

It is a cyclic number.

It is not a de Polignac number, because 72117643 - 2¹ = 72117641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72117641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2773743 + ... + 2773768.

It is an arithmetic number, because the mean of its divisors is an integer number (19416292).

Almost surely, 2^72117643 is an apocalyptic number.

72117643 is a deficient number, since it is larger than the sum of its proper divisors (5547525).

72117643 is a wasteful number, since it uses less digits than its factorization.

72117643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5547524.

The product of its digits is 7056, while the sum is 31.

The square root of 72117643 is about 8492.2107251292. The cubic root of 72117643 is about 416.2432221509.

The spelling of 72117643 in words is "seventy-two million, one hundred seventeen thousand, six hundred forty-three".