39947639 has 4 divisors (see below), whose sum is σ = 40076400. Its totient is φ = 39818880.

The previous prime is 39947599. The next prime is 39947657. The reversal of 39947639 is 93674993.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 39947639 - 2¹² = 39943543 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39947659) 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, 63914 + ... + 64535.

It is an arithmetic number, because the mean of its divisors is an integer number (10019100).

Almost surely, 2^39947639 is an apocalyptic number.

39947639 is a deficient number, since it is larger than the sum of its proper divisors (128761).

39947639 is a wasteful number, since it uses less digits than its factorization.

39947639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128760.

The product of its digits is 1102248, while the sum is 50.

The square root of 39947639 is about 6320.4144642579. The cubic root of 39947639 is about 341.8458974232.

The spelling of 39947639 in words is "thirty-nine million, nine hundred forty-seven thousand, six hundred thirty-nine".