78128825 has 6 divisors (see below), whose sum is σ = 96879774. Its totient is φ = 62503040.

The previous prime is 78128819. The next prime is 78128849. The reversal of 78128825 is 52882187.

It can be written as a sum of positive squares in 3 ways, for example, as 477481 + 77651344 = 691^2 + 8812^2 .

It is not a de Polignac number, because 78128825 - 2⁸ = 78128569 is a prime.

It is a super-2 number, since 2×78128825² = 12208226591761250, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

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, 1562552 + ... + 1562601.

It is an arithmetic number, because the mean of its divisors is an integer number (16146629).

Almost surely, 2^78128825 is an apocalyptic number.

It is an amenable number.

78128825 is a deficient number, since it is larger than the sum of its proper divisors (18750949).

78128825 is a wasteful number, since it uses less digits than its factorization.

78128825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3125163 (or 3125158 counting only the distinct ones).

The product of its digits is 71680, while the sum is 41.

The square root of 78128825 is about 8839.0511368585. The cubic root of 78128825 is about 427.5009632572.

The spelling of 78128825 in words is "seventy-eight million, one hundred twenty-eight thousand, eight hundred twenty-five".