72604561 has 4 divisors (see below), whose sum is σ = 72630324. Its totient is φ = 72578800.

The previous prime is 72604513. The next prime is 72604577. The reversal of 72604561 is 16540627.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 56851600 + 15752961 = 7540^2 + 3969^2 .

It is a 3-Lehmer number, since φ(72604561) divides (72604561-1)³.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72604561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72604591) 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, 8050 + ... + 14491.

It is an arithmetic number, because the mean of its divisors is an integer number (18157581).

Almost surely, 2^72604561 is an apocalyptic number.

It is an amenable number.

72604561 is a deficient number, since it is larger than the sum of its proper divisors (25763).

72604561 is a wasteful number, since it uses less digits than its factorization.

72604561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25762.

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 72604561 is about 8520.8310040747. The cubic root of 72604561 is about 417.1779073603.

The spelling of 72604561 in words is "seventy-two million, six hundred four thousand, five hundred sixty-one".