78692086217 has 4 divisors (see below), whose sum is σ = 80818899396. Its totient is φ = 76565273040.

The previous prime is 78692086163. The next prime is 78692086223. The reversal of 78692086217 is 71268029687.

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 34149561616 + 44542524601 = 184796^2 + 211051^2 .

It is a cyclic number.

It is not a de Polignac number, because 78692086217 - 2⁶ = 78692086153 is a prime.

It is a super-2 number, since 2×78692086217² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78692086717) 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, 1063406534 + ... + 1063406607.

It is an arithmetic number, because the mean of its divisors is an integer number (20204724849).

Almost surely, 2^78692086217 is an apocalyptic number.

It is an amenable number.

78692086217 is a deficient number, since it is larger than the sum of its proper divisors (2126813179).

78692086217 is a wasteful number, since it uses less digits than its factorization.

78692086217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2126813178.

The product of its (nonzero) digits is 4064256, while the sum is 56.

The spelling of 78692086217 in words is "seventy-eight billion, six hundred ninety-two million, eighty-six thousand, two hundred seventeen".