72640423 has 4 divisors (see below), whose sum is σ = 72714280. Its totient is φ = 72566568.

The previous prime is 72640349. The next prime is 72640429. The reversal of 72640423 is 32404627.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32404627 = 73 ⋅443899.

It is a cyclic number.

It is not a de Polignac number, because 72640423 - 2²¹ = 70543271 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 72640391 and 72640400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72640429) 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, 35433 + ... + 37426.

It is an arithmetic number, because the mean of its divisors is an integer number (18178570).

Almost surely, 2^72640423 is an apocalyptic number.

72640423 is a deficient number, since it is larger than the sum of its proper divisors (73857).

72640423 is an equidigital number, since it uses as much as digits as its factorization.

72640423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73856.

The product of its (nonzero) digits is 8064, while the sum is 28.

The square root of 72640423 is about 8522.9351164960. The cubic root of 72640423 is about 417.2465824378.

The spelling of 72640423 in words is "seventy-two million, six hundred forty thousand, four hundred twenty-three".