81082777 has 2 divisors, whose sum is σ = 81082778. Its totient is φ = 81082776.

The previous prime is 81082759. The next prime is 81082801. The reversal of 81082777 is 77728018.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67716441 + 13366336 = 8229^2 + 3656^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81082777 is a prime.

It is not a weakly prime, because it can be changed into another prime (81002777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40541388 + 40541389.

It is an arithmetic number, because the mean of its divisors is an integer number (40541389).

Almost surely, 2^81082777 is an apocalyptic number.

It is an amenable number.

81082777 is a deficient number, since it is larger than the sum of its proper divisors (1).

81082777 is an equidigital number, since it uses as much as digits as its factorization.

81082777 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 43904, while the sum is 40.

The square root of 81082777 is about 9004.5975479196. The cubic root of 81082777 is about 432.8222099165.

The spelling of 81082777 in words is "eighty-one million, eighty-two thousand, seven hundred seventy-seven".