78347765 has 4 divisors (see below), whose sum is σ = 94017324. Its totient is φ = 62678208.

The previous prime is 78347749. The next prime is 78347777. The reversal of 78347765 is 56774387.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56774387 = 5801 ⋅9787.

It can be written as a sum of positive squares in 2 ways, for example, as 18037009 + 60310756 = 4247^2 + 7766^2 .

It is a cyclic number.

It is not a de Polignac number, because 78347765 - 2⁴ = 78347749 is a prime.

It is a super-2 number, since 2×78347765² = 12276744560990450, 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 3 ways as a sum of consecutive naturals, for example, 7834772 + ... + 7834781.

It is an arithmetic number, because the mean of its divisors is an integer number (23504331).

Almost surely, 2^78347765 is an apocalyptic number.

It is an amenable number.

78347765 is a deficient number, since it is larger than the sum of its proper divisors (15669559).

78347765 is a wasteful number, since it uses less digits than its factorization.

78347765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15669558.

The product of its digits is 987840, while the sum is 47.

The square root of 78347765 is about 8851.4272860370. The cubic root of 78347765 is about 427.8999187340.

The spelling of 78347765 in words is "seventy-eight million, three hundred forty-seven thousand, seven hundred sixty-five".