78345689409 has 27 divisors (see below), whose sum is σ = 122557770153. Its totient is φ = 48206014272.

The previous prime is 78345689399. The next prime is 78345689449. The reversal of 78345689409 is 90498654387.

The square root of 78345689409 is 279903.

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

78345689409 is a `hidden beast` number, since 78 + 34 + 56 + 89 + 409 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1406025009 + 76939664400 = 37497^2 + 277380^2 .

It is not a de Polignac number, because 78345689409 - 2⁷ = 78345689281 is a prime.

It is a super-2 number, since 2×78345689409² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78345689449) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 10912629 + ... + 10919805.

Almost surely, 2^78345689409 is an apocalyptic number.

78345689409 is the 279903-rd square number.

78345689409 is the 139952-nd centered octagonal number.

It is an amenable number.

78345689409 is a deficient number, since it is larger than the sum of its proper divisors (44212080744).

78345689409 is an frugal number, since it uses more digits than its factorization.

78345689409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14386 (or 7193 counting only the distinct ones).

The product of its (nonzero) digits is 52254720, while the sum is 63.

The spelling of 78345689409 in words is "seventy-eight billion, three hundred forty-five million, six hundred eighty-nine thousand, four hundred nine".