39993521 has 4 divisors (see below), whose sum is σ = 40033344. Its totient is φ = 39953700.

The previous prime is 39993511. The next prime is 39993529. The reversal of 39993521 is 12539993.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 39993521 - 2¹⁰ = 39992497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (39993529) 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, 18365 + ... + 20426.

It is an arithmetic number, because the mean of its divisors is an integer number (10008336).

Almost surely, 2^39993521 is an apocalyptic number.

It is an amenable number.

39993521 is a deficient number, since it is larger than the sum of its proper divisors (39823).

39993521 is a wasteful number, since it uses less digits than its factorization.

39993521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39822.

The product of its digits is 65610, while the sum is 41.

The square root of 39993521 is about 6324.0430896698. The cubic root of 39993521 is about 341.9767234480.

The spelling of 39993521 in words is "thirty-nine million, nine hundred ninety-three thousand, five hundred twenty-one".