31309005 has 32 divisors (see below), whose sum is σ = 61657344. Its totient is φ = 13211136.

The previous prime is 31309001. The next prime is 31309007. The reversal of 31309005 is 50090313.

It is not a de Polignac number, because 31309005 - 2² = 31309001 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31309001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10104 + ... + 12833.

It is an arithmetic number, because the mean of its divisors is an integer number (1926792).

Almost surely, 2^31309005 is an apocalyptic number.

31309005 is a gapful number since it is divisible by the number (35) formed by its first and last digit.

It is an amenable number.

31309005 is a deficient number, since it is larger than the sum of its proper divisors (30348339).

31309005 is a wasteful number, since it uses less digits than its factorization.

31309005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22965.

The product of its (nonzero) digits is 405, while the sum is 21.

The square root of 31309005 is about 5595.4450225161. The cubic root of 31309005 is about 315.1783822095.

Adding to 31309005 its reverse (50090313), we get a palindrome (81399318).

The spelling of 31309005 in words is "thirty-one million, three hundred nine thousand, five".