77728025 has 6 divisors (see below), whose sum is σ = 96382782. Its totient is φ = 62182400.

The previous prime is 77728019. The next prime is 77728073. The reversal of 77728025 is 52082777.

It can be written as a sum of positive squares in 3 ways, for example, as 1968409 + 75759616 = 1403^2 + 8704^2 .

It is not a de Polignac number, because 77728025 - 2²⁴ = 60950809 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 77728025.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1554536 + ... + 1554585.

It is an arithmetic number, because the mean of its divisors is an integer number (16063797).

Almost surely, 2^77728025 is an apocalyptic number.

It is an amenable number.

77728025 is a deficient number, since it is larger than the sum of its proper divisors (18654757).

77728025 is a wasteful number, since it uses less digits than its factorization.

77728025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3109131 (or 3109126 counting only the distinct ones).

The product of its (nonzero) digits is 54880, while the sum is 38.

The square root of 77728025 is about 8816.3498682845. The cubic root of 77728025 is about 426.7686845759.

The spelling of 77728025 in words is "seventy-seven million, seven hundred twenty-eight thousand, twenty-five".