78766106409 has 27 divisors (see below), whose sum is σ = 120881455383. Its totient is φ = 49412889792.

The previous prime is 78766106399. The next prime is 78766106417. The reversal of 78766106409 is 90460166787.

It is a happy number.

The square root of 78766106409 is 280653.

It is a perfect power (a square), and thus also a powerful number.

78766106409 is a `hidden beast` number, since 78 + 7 + 66 + 106 + 409 = 666.

It can be written as a sum of positive squares in only one way, i.e., 61323093225 + 17443013184 = 247635^2 + 132072^2 .

It is not a de Polignac number, because 78766106409 - 2²⁵ = 78732551977 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78766105409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 14310552 + ... + 14316054.

Almost surely, 2^78766106409 is an apocalyptic number.

78766106409 is the 280653-rd square number.

78766106409 is the 140327-th centered octagonal number.

It is an amenable number.

78766106409 is a deficient number, since it is larger than the sum of its proper divisors (42115348974).

78766106409 is an frugal number, since it uses more digits than its factorization.

78766106409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11046 (or 5523 counting only the distinct ones).

The product of its (nonzero) digits is 3048192, while the sum is 54.

The spelling of 78766106409 in words is "seventy-eight billion, seven hundred sixty-six million, one hundred six thousand, four hundred nine".