19531 has 2 divisors, whose sum is σ = 19532. Its totient is φ = 19530.

The previous prime is 19507. The next prime is 19541. The reversal of 19531 is 13591.

19531 is nontrivially palindromic in base 5.

It is a strong prime.

It is an emirp because it is prime and its reverse (13591) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19531 - 2⁷ = 19403 is a prime.

It is a super-2 number, since 2×19531² = 762919922, which contains 22 as substring.

19531 is a nontrivial repdigit in base 5.

It is a plaindrome in base 5.

It is a nialpdrome in base 5.

It is a zygodrome in base 5.

It is a junction number, because it is equal to n+sod(n) for n = 19499 and 19508.

It is not a weakly prime, because it can be changed into another prime (19501) by changing a digit.

It is a nontrivial repunit in base 5.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9765 + 9766.

It is an arithmetic number, because the mean of its divisors is an integer number (9766).

2¹⁹⁵³¹ is an apocalyptic number.

19531 is the 63-rd centered decagonal number.

19531 is a deficient number, since it is larger than the sum of its proper divisors (1).

19531 is an equidigital number, since it uses as much as digits as its factorization.

19531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 135, while the sum is 19.

The square root of 19531 is about 139.7533541637. The cubic root of 19531 is about 26.9303187217.

The spelling of 19531 in words is "nineteen thousand, five hundred thirty-one".