71531431 has 2 divisors, whose sum is σ = 71531432. Its totient is φ = 71531430.

The previous prime is 71531413. The next prime is 71531441. The reversal of 71531431 is 13413517.

Together with previous prime (71531413) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 71531431 - 2⁷ = 71531303 is a prime.

It is a super-2 number, since 2×71531431² = 10233491241815522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 71531396 and 71531405.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71531401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35765715 + 35765716.

It is an arithmetic number, because the mean of its divisors is an integer number (35765716).

Almost surely, 2^71531431 is an apocalyptic number.

71531431 is a deficient number, since it is larger than the sum of its proper divisors (1).

71531431 is an equidigital number, since it uses as much as digits as its factorization.

71531431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1260, while the sum is 25.

The square root of 71531431 is about 8457.6256124281. The cubic root of 71531431 is about 415.1123342294.

Adding to 71531431 its reverse (13413517), we get a palindrome (84944948).

The spelling of 71531431 in words is "seventy-one million, five hundred thirty-one thousand, four hundred thirty-one".