78398659 has 4 divisors (see below), whose sum is σ = 80927680. Its totient is φ = 75869640.

The previous prime is 78398657. The next prime is 78398681. The reversal of 78398659 is 95689387.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 95689387 = 823 ⋅116269.

It is a cyclic number.

It is not a de Polignac number, because 78398659 - 2¹ = 78398657 is a prime.

It is a super-2 number, since 2×78398659² = 12292699465996562, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78398657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1264464 + ... + 1264525.

It is an arithmetic number, because the mean of its divisors is an integer number (20231920).

Almost surely, 2^78398659 is an apocalyptic number.

78398659 is a deficient number, since it is larger than the sum of its proper divisors (2529021).

78398659 is a wasteful number, since it uses less digits than its factorization.

78398659 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2529020.

The product of its digits is 3265920, while the sum is 55.

The square root of 78398659 is about 8854.3017228915. The cubic root of 78398659 is about 427.9925519856.

The spelling of 78398659 in words is "seventy-eight million, three hundred ninety-eight thousand, six hundred fifty-nine".