78390625 has 28 divisors (see below), whose sum is σ = 101951820. Its totient is φ = 60200000.

The previous prime is 78390619. The next prime is 78390629. The reversal of 78390625 is 52609387.

It can be written as a sum of positive squares in 14 ways, for example, as 76055841 + 2334784 = 8721^2 + 1528^2 .

It is not a de Polignac number, because 78390625 - 2⁷ = 78390497 is a prime.

It is a super-2 number, since 2×78390625² = 12290180175781250, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78390629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 453039 + ... + 453211.

Almost surely, 2^78390625 is an apocalyptic number.

It is an amenable number.

78390625 is a deficient number, since it is larger than the sum of its proper divisors (23561195).

78390625 is an frugal number, since it uses more digits than its factorization.

78390625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232 (or 207 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 40.

The square root of 78390625 is about 8853.8480334824. The cubic root of 78390625 is about 427.9779317966.

The spelling of 78390625 in words is "seventy-eight million, three hundred ninety thousand, six hundred twenty-five".