81716671 has 4 divisors (see below), whose sum is σ = 86523552. Its totient is φ = 76909792.

The previous prime is 81716647. The next prime is 81716681. The reversal of 81716671 is 17661718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17661718 = 2 ⋅8830859.

It is a cyclic number.

It is not a de Polignac number, because 81716671 - 2¹³ = 81708479 is a prime.

It is a super-2 number, since 2×81716671² = 13355228638644482, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81716671.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81716611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2403415 + ... + 2403448.

It is an arithmetic number, because the mean of its divisors is an integer number (21630888).

Almost surely, 2^81716671 is an apocalyptic number.

81716671 is a deficient number, since it is larger than the sum of its proper divisors (4806881).

81716671 is a wasteful number, since it uses less digits than its factorization.

81716671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4806880.

The product of its digits is 14112, while the sum is 37.

The square root of 81716671 is about 9039.7273742077. The cubic root of 81716671 is about 433.9471981604.

The spelling of 81716671 in words is "eighty-one million, seven hundred sixteen thousand, six hundred seventy-one".