81743071 has 2 divisors, whose sum is σ = 81743072. Its totient is φ = 81743070.

The previous prime is 81743069. The next prime is 81743147. The reversal of 81743071 is 17034718.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81743071 - 2¹ = 81743069 is a prime.

It is a super-2 number, since 2×81743071² = 13363859313022082, which contains 22 as substring.

Together with 81743069, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81743041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40871535 + 40871536.

It is an arithmetic number, because the mean of its divisors is an integer number (40871536).

Almost surely, 2^81743071 is an apocalyptic number.

81743071 is a deficient number, since it is larger than the sum of its proper divisors (1).

81743071 is an equidigital number, since it uses as much as digits as its factorization.

81743071 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4704, while the sum is 31.

The square root of 81743071 is about 9041.1874773173. The cubic root of 81743071 is about 433.9939245400.

Adding to 81743071 its reverse (17034718), we get a palindrome (98777789).

The spelling of 81743071 in words is "eighty-one million, seven hundred forty-three thousand, seventy-one".