81776688 has 80 divisors (see below), whose sum is σ = 246412800. Its totient is φ = 23360064.

The previous prime is 81776683. The next prime is 81776693. The reversal of 81776688 is 88667718.

It is an interprime number because it is at equal distance from previous prime (81776683) and next prime (81776693).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 81776688.

It is not an unprimeable number, because it can be changed into a prime (81776683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13981 + ... + 18947.

It is an arithmetic number, because the mean of its divisors is an integer number (3080160).

Almost surely, 2^81776688 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81776688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123206400).

81776688 is an abundant number, since it is smaller than the sum of its proper divisors (164636112).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81776688 is a wasteful number, since it uses less digits than its factorization.

81776688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4999 (or 4979 counting only the distinct ones).

The product of its digits is 903168, while the sum is 51.

The square root of 81776688 is about 9043.0463893535. The cubic root of 81776688 is about 434.0534100068.

The spelling of 81776688 in words is "eighty-one million, seven hundred seventy-six thousand, six hundred eighty-eight".