78765625 has 21 divisors (see below), whose sum is σ = 99862003. Its totient is φ = 62125000.

The previous prime is 78765619. The next prime is 78765647. The reversal of 78765625 is 52656787.

The square root of 78765625 is 8875.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 3 ways, for example, as 69006249 + 9759376 = 8307^2 + 3124^2 .

It is not a de Polignac number, because 78765625 - 2⁷ = 78765497 is a prime.

It is a Smith number, since the sum of its digits (46) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 1109340 + ... + 1109410.

Almost surely, 2^78765625 is an apocalyptic number.

78765625 is the 8875-th square number.

78765625 is the 4438-th centered octagonal number.

It is an amenable number.

78765625 is a deficient number, since it is larger than the sum of its proper divisors (21096378).

78765625 is an frugal number, since it uses more digits than its factorization.

78765625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172 (or 76 counting only the distinct ones).

The product of its digits is 705600, while the sum is 46.

The cubic root of 78765625 is about 428.6592908484.

Multiplying 78765625 by its product of digits (705600), we get a square (55577025000000 = 7455000²).

It can be divided in two parts, 78 and 765625, that added together give a triangular number (765703 = T₁₂₃₇).

The spelling of 78765625 in words is "seventy-eight million, seven hundred sixty-five thousand, six hundred twenty-five".