81167665 has 8 divisors (see below), whose sum is σ = 100760040. Its totient is φ = 62694912.

The previous prime is 81167663. The next prime is 81167683. The reversal of 81167665 is 56676118.

It can be written as a sum of positive squares in 4 ways, for example, as 27468081 + 53699584 = 5241^2 + 7328^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81167665 - 2¹ = 81167663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81167663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 279744 + ... + 280033.

It is an arithmetic number, because the mean of its divisors is an integer number (12595005).

Almost surely, 2^81167665 is an apocalyptic number.

It is an amenable number.

81167665 is a deficient number, since it is larger than the sum of its proper divisors (19592375).

81167665 is a wasteful number, since it uses less digits than its factorization.

81167665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 559811.

The product of its digits is 60480, while the sum is 40.

The square root of 81167665 is about 9009.3099069796. The cubic root of 81167665 is about 432.9732021028.

The spelling of 81167665 in words is "eighty-one million, one hundred sixty-seven thousand, six hundred sixty-five".