71143781 has 2 divisors, whose sum is σ = 71143782. Its totient is φ = 71143780.

The previous prime is 71143769. The next prime is 71143811. The reversal of 71143781 is 18734117.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53217025 + 17926756 = 7295^2 + 4234^2 .

It is a cyclic number.

It is not a de Polignac number, because 71143781 - 2¹⁸ = 70881637 is a prime.

It is a super-2 number, since 2×71143781² = 10122875149951922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71143381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35571890 + 35571891.

It is an arithmetic number, because the mean of its divisors is an integer number (35571891).

Almost surely, 2^71143781 is an apocalyptic number.

It is an amenable number.

71143781 is a deficient number, since it is larger than the sum of its proper divisors (1).

71143781 is an equidigital number, since it uses as much as digits as its factorization.

71143781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4704, while the sum is 32.

The square root of 71143781 is about 8434.6772908037. The cubic root of 71143781 is about 414.3611033349.

Adding to 71143781 its reverse (18734117), we get a palindrome (89877898).

The spelling of 71143781 in words is "seventy-one million, one hundred forty-three thousand, seven hundred eighty-one".