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31213 = 7413
BaseRepresentation
bin111100111101101
31120211001
413213231
51444323
6400301
7160000
oct74755
946731
1031213
11214a6
1216091
1311290
14b537
1593ad
hex79ed

31213 has 10 divisors (see below), whose sum is σ = 39214. Its totient is φ = 24696.

The previous prime is 31193. The next prime is 31219.

It can be divided in two parts, 312 and 13, that added together give a triangular number (325 = T25).

31213 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in only one way, i.e., 21609 + 9604 = 147^2 + 98^2 .

It is not a de Polignac number, because 31213 - 25 = 31181 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31219) 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 9 ways as a sum of consecutive naturals, for example, 2395 + ... + 2407.

231213 is an apocalyptic number.

It is an amenable number.

31213 is a deficient number, since it is larger than the sum of its proper divisors (8001).

31213 is an frugal number, since it uses more digits than its factorization.

31213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41 (or 20 counting only the distinct ones).

The product of its digits is 18, while the sum is 10.

The square root of 31213 is about 176.6720124977. The cubic root of 31213 is about 31.4855901169.

The spelling of 31213 in words is "thirty-one thousand, two hundred thirteen".

Divisors: 1 7 13 49 91 343 637 2401 4459 31213