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31279 = 311009

31279 has 4 divisors (see below), whose sum is σ = 32320. Its totient is φ = 30240.

The previous prime is 31277. The next prime is 31307. The reversal of 31279 is 97213.

31279 is nontrivially palindromic in base 2, base 8 and base 13.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 31279 - 21 = 31277 is a prime.

It is a Duffinian number.

31279 is a modest number, since divided by 279 gives 31 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31271) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 474 + ... + 535.

It is an arithmetic number, because the mean of its divisors is an integer number (8080).

231279 is an apocalyptic number.

31279 is a deficient number, since it is larger than the sum of its proper divisors (1041).

31279 is a wasteful number, since it uses less digits than its factorization.

31279 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1040.

The product of its digits is 378, while the sum is 22.

The square root of 31279 is about 176.8587006624. The cubic root of 31279 is about 31.5077666244.

It can be divided in two parts, 3127 and 9, that added together give a square (3136 = 562).

The spelling of 31279 in words is "thirty-one thousand, two hundred seventy-nine".

Divisors: 1 31 1009 31279