72391643 has 4 divisors (see below), whose sum is σ = 73618680. Its totient is φ = 71164608.

The previous prime is 72391639. The next prime is 72391667. The reversal of 72391643 is 34619327.

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 72391643 - 2² = 72391639 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72391673) 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, 613430 + ... + 613547.

It is an arithmetic number, because the mean of its divisors is an integer number (18404670).

Almost surely, 2^72391643 is an apocalyptic number.

72391643 is a deficient number, since it is larger than the sum of its proper divisors (1227037).

72391643 is a wasteful number, since it uses less digits than its factorization.

72391643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1227036.

The product of its digits is 27216, while the sum is 35.

The square root of 72391643 is about 8508.3278615719. The cubic root of 72391643 is about 416.7697068542.

The spelling of 72391643 in words is "seventy-two million, three hundred ninety-one thousand, six hundred forty-three".