78020689 has 4 divisors (see below), whose sum is σ = 78825124. Its totient is φ = 77216256.

The previous prime is 78020687. The next prime is 78020699. The reversal of 78020689 is 98602087.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98602087 = 251 ⋅392837.

It can be written as a sum of positive squares in 2 ways, for example, as 62536464 + 15484225 = 7908^2 + 3935^2 .

It is a cyclic number.

It is not a de Polignac number, because 78020689 - 2¹ = 78020687 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78020681) 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, 402072 + ... + 402265.

It is an arithmetic number, because the mean of its divisors is an integer number (19706281).

Almost surely, 2^78020689 is an apocalyptic number.

It is an amenable number.

78020689 is a deficient number, since it is larger than the sum of its proper divisors (804435).

78020689 is an equidigital number, since it uses as much as digits as its factorization.

78020689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 804434.

The product of its (nonzero) digits is 48384, while the sum is 40.

The square root of 78020689 is about 8832.9320726472. The cubic root of 78020689 is about 427.3036413412.

The spelling of 78020689 in words is "seventy-eight million, twenty thousand, six hundred eighty-nine".