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31693 = 41773

31693 has 4 divisors (see below), whose sum is σ = 32508. Its totient is φ = 30880.

The previous prime is 31687. The next prime is 31699. The reversal of 31693 is 39613.

31693 = T17 + T18 + ... + T57.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 39613 = 75659.

It is an interprime number because it is at equal distance from previous prime (31687) and next prime (31699).

It can be written as a sum of positive squares in 2 ways, for example, as 1764 + 29929 = 42^2 + 173^2 .

It is a cyclic number.

It is not a de Polignac number, because 31693 - 29 = 31181 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an Ulam number.

It is a Duffinian number.

It is a plaindrome in base 13 and base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31699) 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, 346 + ... + 427.

It is an arithmetic number, because the mean of its divisors is an integer number (8127).

231693 is an apocalyptic number.

It is an amenable number.

31693 is a deficient number, since it is larger than the sum of its proper divisors (815).

31693 is an equidigital number, since it uses as much as digits as its factorization.

31693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 814.

The product of its digits is 486, while the sum is 22.

The square root of 31693 is about 178.0252791038. The cubic root of 31693 is about 31.6461670956.

The spelling of 31693 in words is "thirty-one thousand, six hundred ninety-three".

Divisors: 1 41 773 31693