81011071 has 16 divisors (see below), whose sum is σ = 84913920. Its totient is φ = 77237440.

The previous prime is 81011059. The next prime is 81011081. The reversal of 81011071 is 17011018.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81011071 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81011081) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 347571 + ... + 347803.

It is an arithmetic number, because the mean of its divisors is an integer number (5307120).

Almost surely, 2^81011071 is an apocalyptic number.

81011071 is a deficient number, since it is larger than the sum of its proper divisors (3902849).

81011071 is a wasteful number, since it uses less digits than its factorization.

81011071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446.

The product of its (nonzero) digits is 56, while the sum is 19.

The square root of 81011071 is about 9000.6150345407. The cubic root of 81011071 is about 432.6945827189.

Adding to 81011071 its reverse (17011018), we get a palindrome (98022089).

It can be divided in two parts, 810 and 11071, that added together give a square (11881 = 109²).

The spelling of 81011071 in words is "eighty-one million, eleven thousand, seventy-one".