31431 has 4 divisors (see below), whose sum is σ = 41912. Its totient is φ = 20952.

The previous prime is 31397. The next prime is 31469. The reversal of 31431 is 13413.

Adding to 31431 its reverse (13413), we get a palindrome (44844).

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

It is not a de Polignac number, because 31431 - 2^{11} = 29383 is a prime.

It is a super-2 number, since 2×31431^{2} = 1975815522, which contains 22 as substring.

It is an Ulam number.

It is a D-number.

It is a lonely number, since its distance to closest prime (31397) sets a new record.

It is a Duffinian number.

It is a nialpdrome in base 14.

It is a congruent number.

It is an inconsummate number, since it does not exist a number *n* which divided by its sum of digits gives 31431.

It is not an unprimeable number, because it can be changed into a prime (31481) 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, 5236 + ... + 5241.

It is an arithmetic number, because the mean of its divisors is an integer number (10478).

2^{31431} is an apocalyptic number.

31431 is a deficient number, since it is larger than the sum of its proper divisors (10481).

31431 is a wasteful number, since it uses less digits than its factorization.

31431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10480.

The product of its digits is 36, while the sum is 12.

The square root of 31431 is about 177.2879014485. The cubic root of 31431 is about 31.5587214050.

The spelling of 31431 in words is "thirty-one thousand, four hundred thirty-one".

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