78228338774665 has 16 divisors (see below), whose sum is σ = 100757596057488. Its totient is φ = 58094469789696.

The previous prime is 78228338774639. The next prime is 78228338774669. The reversal of 78228338774665 is 56647783382287.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 3558640782096 + 74669697992569 = 1886436^2 + 8641163^2 .

It is a cyclic number.

It is not a de Polignac number, because 78228338774665 - 2⁵ = 78228338774633 is a prime.

It is a super-2 number, since 2×78228338774665² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 78228338774591 and 78228338774600.

It is not an unprimeable number, because it can be changed into a prime (78228338774669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6303647202 + ... + 6303659611.

It is an arithmetic number, because the mean of its divisors is an integer number (6297349753593).

Almost surely, 2^{78228338774665} is an apocalyptic number.

It is an amenable number.

78228338774665 is a deficient number, since it is larger than the sum of its proper divisors (22529257282823).

78228338774665 is a wasteful number, since it uses less digits than its factorization.

78228338774665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12607306908.

The product of its digits is 4551966720, while the sum is 76.

The spelling of 78228338774665 in words is "seventy-eight trillion, two hundred twenty-eight billion, three hundred thirty-eight million, seven hundred seventy-four thousand, six hundred sixty-five".