39728609 has 8 divisors (see below), whose sum is σ = 42244488. Its totient is φ = 37232640.

The previous prime is 39728599. The next prime is 39728617. The reversal of 39728609 is 90682793.

It can be written as a sum of positive squares in 4 ways, for example, as 7840000 + 31888609 = 2800^2 + 5647^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 39728609 - 2¹² = 39724513 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 39728609.

It is not an unprimeable number, because it can be changed into a prime (39728669) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 752 + ... + 8945.

It is an arithmetic number, because the mean of its divisors is an integer number (5280561).

Almost surely, 2^39728609 is an apocalyptic number.

It is an amenable number.

39728609 is a deficient number, since it is larger than the sum of its proper divisors (2515879).

39728609 is a wasteful number, since it uses less digits than its factorization.

39728609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9955.

The product of its (nonzero) digits is 163296, while the sum is 44.

The square root of 39728609 is about 6303.0634615241. The cubic root of 39728609 is about 341.2199800058.

The spelling of 39728609 in words is "thirty-nine million, seven hundred twenty-eight thousand, six hundred nine".