81778330 has 24 divisors (see below), whose sum is σ = 156374748. Its totient is φ = 30786048.

The previous prime is 81778327. The next prime is 81778343. The reversal of 81778330 is 3387718.

It can be written as a sum of positive squares in 6 ways, for example, as 39904489 + 41873841 = 6317^2 + 6471^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81778330.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11259 + ... + 17038.

Almost surely, 2^81778330 is an apocalyptic number.

81778330 is a deficient number, since it is larger than the sum of its proper divisors (74596418).

81778330 is a wasteful number, since it uses less digits than its factorization.

81778330 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28338 (or 28321 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 37.

The square root of 81778330 is about 9043.1371768872. The cubic root of 81778330 is about 434.0563151172.

The spelling of 81778330 in words is "eighty-one million, seven hundred seventy-eight thousand, three hundred thirty".