78565397 has 4 divisors (see below), whose sum is σ = 79260780. Its totient is φ = 77870016.

The previous prime is 78565391. The next prime is 78565453. The reversal of 78565397 is 79356587.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10023556 + 68541841 = 3166^2 + 8279^2 .

It is a cyclic number.

It is not a de Polignac number, because 78565397 - 2⁸ = 78565141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78565391) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 347522 + ... + 347747.

It is an arithmetic number, because the mean of its divisors is an integer number (19815195).

Almost surely, 2^78565397 is an apocalyptic number.

It is an amenable number.

78565397 is a deficient number, since it is larger than the sum of its proper divisors (695383).

78565397 is a wasteful number, since it uses less digits than its factorization.

78565397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 695382.

The product of its digits is 1587600, while the sum is 50.

The square root of 78565397 is about 8863.7123712359. The cubic root of 78565397 is about 428.2957548357.

The spelling of 78565397 in words is "seventy-eight million, five hundred sixty-five thousand, three hundred ninety-seven".