9778078685 has 4 divisors (see below), whose sum is σ = 11733694428. Its totient is φ = 7822462944.

The previous prime is 9778078679. The next prime is 9778078721. The reversal of 9778078685 is 5868708779.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5868708779 = 4201 ⋅1396979.

It can be written as a sum of positive squares in 2 ways, for example, as 5909611876 + 3868466809 = 76874^2 + 62197^2 .

It is a cyclic number.

It is not a de Polignac number, because 9778078685 - 2²² = 9773884381 is a prime.

It is a super-2 number, since 2×9778078685² (a number of 21 digits) 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, 977807864 + ... + 977807873.

It is an arithmetic number, because the mean of its divisors is an integer number (2933423607).

Almost surely, 2^9778078685 is an apocalyptic number.

It is an amenable number.

9778078685 is a deficient number, since it is larger than the sum of its proper divisors (1955615743).

9778078685 is a wasteful number, since it uses less digits than its factorization.

9778078685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1955615742.

The product of its (nonzero) digits is 47416320, while the sum is 65.

The square root of 9778078685 is about 98884.1680199616. The cubic root of 9778078685 is about 2138.3781554596.

The spelling of 9778078685 in words is "nine billion, seven hundred seventy-eight million, seventy-eight thousand, six hundred eighty-five".