39778939 has 4 divisors (see below), whose sum is σ = 39801280. Its totient is φ = 39756600.

The previous prime is 39778927. The next prime is 39778969. The reversal of 39778939 is 93987793.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93987793 = 269 ⋅349397.

It is a cyclic number.

It is not a de Polignac number, because 39778939 - 2²⁵ = 6224507 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 39778939.

It is not an unprimeable number, because it can be changed into a prime (39778919) 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, 8244 + ... + 12145.

It is an arithmetic number, because the mean of its divisors is an integer number (9950320).

Almost surely, 2^39778939 is an apocalyptic number.

39778939 is a deficient number, since it is larger than the sum of its proper divisors (22341).

39778939 is a wasteful number, since it uses less digits than its factorization.

39778939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22340.

The product of its digits is 2571912, while the sum is 55.

The square root of 39778939 is about 6307.0547008885. The cubic root of 39778939 is about 341.3640101730.

The spelling of 39778939 in words is "thirty-nine million, seven hundred seventy-eight thousand, nine hundred thirty-nine".