39905213 has 4 divisors (see below), whose sum is σ = 39925248. Its totient is φ = 39885180.

The previous prime is 39905183. The next prime is 39905221. The reversal of 39905213 is 31250993.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31250993 = 4483 ⋅6971.

It is a cyclic number.

It is not a de Polignac number, because 39905213 - 2¹⁴ = 39888829 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 39905213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39905233) 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, 6653 + ... + 11138.

It is an arithmetic number, because the mean of its divisors is an integer number (9981312).

Almost surely, 2^39905213 is an apocalyptic number.

It is an amenable number.

39905213 is a deficient number, since it is larger than the sum of its proper divisors (20035).

39905213 is a wasteful number, since it uses less digits than its factorization.

39905213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20034.

The product of its (nonzero) digits is 7290, while the sum is 32.

The square root of 39905213 is about 6317.0573054232. The cubic root of 39905213 is about 341.7248365232.

The spelling of 39905213 in words is "thirty-nine million, nine hundred five thousand, two hundred thirteen".