39131221 has 4 divisors (see below), whose sum is σ = 39159712. Its totient is φ = 39102732.

The previous prime is 39131189. The next prime is 39131249. The reversal of 39131221 is 12213193.

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 39131221 - 2⁵ = 39131189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 39131192 and 39131201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39131251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12075 + ... + 14968.

It is an arithmetic number, because the mean of its divisors is an integer number (9789928).

Almost surely, 2^39131221 is an apocalyptic number.

It is an amenable number.

39131221 is a deficient number, since it is larger than the sum of its proper divisors (28491).

39131221 is a wasteful number, since it uses less digits than its factorization.

39131221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28490.

The product of its digits is 324, while the sum is 22.

The square root of 39131221 is about 6255.4952641657. The cubic root of 39131221 is about 339.5010588324.

The spelling of 39131221 in words is "thirty-nine million, one hundred thirty-one thousand, two hundred twenty-one".