81063665 has 8 divisors (see below), whose sum is σ = 97567080. Its totient is φ = 64657152.

The previous prime is 81063641. The next prime is 81063677. The reversal of 81063665 is 56636018.

It can be written as a sum of positive squares in 4 ways, for example, as 4255969 + 76807696 = 2063^2 + 8764^2 .

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 81063665 - 2¹⁶ = 80998129 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22370 + ... + 25739.

It is an arithmetic number, because the mean of its divisors is an integer number (12195885).

Almost surely, 2^81063665 is an apocalyptic number.

It is an amenable number.

81063665 is a deficient number, since it is larger than the sum of its proper divisors (16503415).

81063665 is a wasteful number, since it uses less digits than its factorization.

81063665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48451.

The product of its (nonzero) digits is 25920, while the sum is 35.

The square root of 81063665 is about 9003.5362497188. The cubic root of 81063665 is about 432.7882004413.

The spelling of 81063665 in words is "eighty-one million, sixty-three thousand, six hundred sixty-five".