77780728 has 8 divisors (see below), whose sum is σ = 145838880. Its totient is φ = 38890360.

The previous prime is 77780707. The next prime is 77780741. The reversal of 77780728 is 82708777.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4861288 + ... + 4861303.

It is an arithmetic number, because the mean of its divisors is an integer number (18229860).

Almost surely, 2^77780728 is an apocalyptic number.

It is an amenable number.

77780728 is a deficient number, since it is larger than the sum of its proper divisors (68058152).

77780728 is a wasteful number, since it uses less digits than its factorization.

77780728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9722597 (or 9722593 counting only the distinct ones).

The product of its (nonzero) digits is 307328, while the sum is 46.

The square root of 77780728 is about 8819.3382971740. The cubic root of 77780728 is about 426.8651187273.

The spelling of 77780728 in words is "seventy-seven million, seven hundred eighty thousand, seven hundred twenty-eight".