78345491217 has 16 divisors (see below), whose sum is σ = 119434033152. Its totient is φ = 44749941840.

The previous prime is 78345491209. The next prime is 78345491299. The reversal of 78345491217 is 71219454387.

It is not a de Polignac number, because 78345491217 - 2³ = 78345491209 is a prime.

It is a super-2 number, since 2×78345491217² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78345491217.

It is not an unprimeable number, because it can be changed into a prime (78345491207) 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, 736953 + ... + 836534.

It is an arithmetic number, because the mean of its divisors is an integer number (7464627072).

Almost surely, 2^78345491217 is an apocalyptic number.

It is an amenable number.

78345491217 is a deficient number, since it is larger than the sum of its proper divisors (41088541935).

78345491217 is a wasteful number, since it uses less digits than its factorization.

78345491217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1575868.

The product of its digits is 1693440, while the sum is 51.

The spelling of 78345491217 in words is "seventy-eight billion, three hundred forty-five million, four hundred ninety-one thousand, two hundred seventeen".