81763665 has 16 divisors (see below), whose sum is σ = 130958208. Its totient is φ = 43561856.

The previous prime is 81763663. The next prime is 81763667. The reversal of 81763665 is 56636718.

It is an interprime number because it is at equal distance from previous prime (81763663) and next prime (81763667).

It is a cyclic number.

It is not a de Polignac number, because 81763665 - 2¹ = 81763663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81763663) 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, 16117 + ... + 20573.

It is an arithmetic number, because the mean of its divisors is an integer number (8184888).

Almost surely, 2^81763665 is an apocalyptic number.

It is an amenable number.

81763665 is a deficient number, since it is larger than the sum of its proper divisors (49194543).

81763665 is a wasteful number, since it uses less digits than its factorization.

81763665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5688.

The product of its digits is 181440, while the sum is 42.

The square root of 81763665 is about 9042.3263046630. The cubic root of 81763665 is about 434.0303676713.

It can be divided in two parts, 81763 and 665, that added together give a palindrome (82428).

The spelling of 81763665 in words is "eighty-one million, seven hundred sixty-three thousand, six hundred sixty-five".