871531 has 2 divisors, whose sum is σ = 871532. Its totient is φ = 871530.

The previous prime is 871517. The next prime is 871553. The reversal of 871531 is 135178.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-871531 is a prime.

It is a super-2 number, since 2×871531² = 1519132567922, which contains 22 as substring.

871531 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 871496 and 871505.

It is not a weakly prime, because it can be changed into another prime (871571) 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 as a sum of consecutive naturals, namely, 435765 + 435766.

It is an arithmetic number, because the mean of its divisors is an integer number (435766).

2⁸⁷¹⁵³¹ is an apocalyptic number.

871531 is the 418-th centered decagonal number.

871531 is a deficient number, since it is larger than the sum of its proper divisors (1).

871531 is an equidigital number, since it uses as much as digits as its factorization.

871531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 840, while the sum is 25.

The square root of 871531 is about 933.5582467099. The cubic root of 871531 is about 95.5199925250.

The spelling of 871531 in words is "eight hundred seventy-one thousand, five hundred thirty-one".