31209 has 8 divisors (see below), whose sum is σ = 42432. Its totient is φ = 20400.

The previous prime is 31193. The next prime is 31219. The reversal of 31209 is 90213.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 31209 - 2⁴ = 31193 is a prime.

It is a plaindrome in base 13.

It is a nialpdrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (31219) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 252 + ... + 354.

It is an arithmetic number, because the mean of its divisors is an integer number (5304).

2³¹²⁰⁹ is an apocalyptic number.

It is an amenable number.

31209 is a deficient number, since it is larger than the sum of its proper divisors (11223).

31209 is a wasteful number, since it uses less digits than its factorization.

31209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207.

The product of its (nonzero) digits is 54, while the sum is 15.

The square root of 31209 is about 176.6606917229. The cubic root of 31209 is about 31.4842450818.

The spelling of 31209 in words is "thirty-one thousand, two hundred nine".