31005 has 24 divisors (see below), whose sum is σ = 58968. Its totient is φ = 14976.

The previous prime is 30983. The next prime is 31013. The reversal of 31005 is 50013.

It can be written as a sum of positive squares in 4 ways, for example, as 1764 + 29241 = 42^2 + 171^2 .

It is not a de Polignac number, because 31005 - 2⁶ = 30941 is a prime.

It is a super-2 number, since 2×31005² = 1922620050, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 559 + ... + 611.

It is an arithmetic number, because the mean of its divisors is an integer number (2457).

2³¹⁰⁰⁵ is an apocalyptic number.

It is an amenable number.

31005 is a deficient number, since it is larger than the sum of its proper divisors (27963).

31005 is a wasteful number, since it uses less digits than its factorization.

31005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77 (or 74 counting only the distinct ones).

The product of its (nonzero) digits is 15, while the sum is 9.

The square root of 31005 is about 176.0823670900. The cubic root of 31005 is about 31.4154953474.

Adding to 31005 its reverse (50013), we get a palindrome (81018).

The spelling of 31005 in words is "thirty-one thousand, five".