77081728 has 16 divisors (see below), whose sum is σ = 153561510. Its totient is φ = 38540800.

The previous prime is 77081699. The next prime is 77081747. The reversal of 77081728 is 82718077.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 39037504 + 38044224 = 6248^2 + 6168^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 300973 + ... + 301228.

Almost surely, 2^77081728 is an apocalyptic number.

It is an amenable number.

77081728 is a deficient number, since it is larger than the sum of its proper divisors (76479782).

77081728 is an equidigital number, since it uses as much as digits as its factorization.

77081728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 602215 (or 602203 counting only the distinct ones).

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

The square root of 77081728 is about 8779.6200373365. The cubic root of 77081728 is about 425.5825515299.

The spelling of 77081728 in words is "seventy-seven million, eighty-one thousand, seven hundred twenty-eight".