72387691 has 4 divisors (see below), whose sum is σ = 72404800. Its totient is φ = 72370584.

The previous prime is 72387617. The next prime is 72387709. The reversal of 72387691 is 19678327.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 19678327 = 29 ⋅678563.

It is a cyclic number.

It is not a de Polignac number, because 72387691 - 2¹³ = 72379499 is a prime.

It is a super-2 number, since 2×72387691² = 10479955616622962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72382691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2950 + ... + 12388.

It is an arithmetic number, because the mean of its divisors is an integer number (18101200).

Almost surely, 2^72387691 is an apocalyptic number.

72387691 is a deficient number, since it is larger than the sum of its proper divisors (17109).

72387691 is an equidigital number, since it uses as much as digits as its factorization.

72387691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17108.

The product of its digits is 127008, while the sum is 43.

The square root of 72387691 is about 8508.0956153536. The cubic root of 72387691 is about 416.7621226277.

The spelling of 72387691 in words is "seventy-two million, three hundred eighty-seven thousand, six hundred ninety-one".