39978309 has 16 divisors (see below), whose sum is σ = 61103232. Its totient is φ = 22775808.

The previous prime is 39978293. The next prime is 39978311. The reversal of 39978309 is 90387993.

It is not a de Polignac number, because 39978309 - 2⁴ = 39978293 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39978319) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4717 + ... + 10109.

It is an arithmetic number, because the mean of its divisors is an integer number (3818952).

Almost surely, 2^39978309 is an apocalyptic number.

It is an amenable number.

39978309 is a deficient number, since it is larger than the sum of its proper divisors (21124923).

39978309 is a wasteful number, since it uses less digits than its factorization.

39978309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5756.

The product of its (nonzero) digits is 367416, while the sum is 48.

The square root of 39978309 is about 6322.8402636790. The cubic root of 39978309 is about 341.9333596773.

The spelling of 39978309 in words is "thirty-nine million, nine hundred seventy-eight thousand, three hundred nine".