31409 has 6 divisors (see below), whose sum is σ = 36594. Its totient is φ = 26880.

The previous prime is 31397. The next prime is 31469. The reversal of 31409 is 90413.

It can be written as a sum of positive squares in only one way, i.e., 30625 + 784 = 175^2 + 28^2 .

It is not a de Polignac number, because 31409 - 2⁴ = 31393 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (31469) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 272 + ... + 369.

It is an arithmetic number, because the mean of its divisors is an integer number (6099).

2³¹⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

31409 is a deficient number, since it is larger than the sum of its proper divisors (5185).

31409 is an equidigital number, since it uses as much as digits as its factorization.

31409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 655 (or 648 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 31409 is about 177.2258446164. The cubic root of 31409 is about 31.5513565537.

The spelling of 31409 in words is "thirty-one thousand, four hundred nine".