78423869 has 4 divisors (see below), whose sum is σ = 78996444. Its totient is φ = 77851296.

The previous prime is 78423833. The next prime is 78423883. The reversal of 78423869 is 96832487.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 96832487 = 67 ⋅1445261.

It can be written as a sum of positive squares in 2 ways, for example, as 34692100 + 43731769 = 5890^2 + 6613^2 .

It is a cyclic number.

It is not a de Polignac number, because 78423869 - 2¹⁶ = 78358333 is a prime.

It is a super-2 number, since 2×78423869² = 12300606457858322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78423809) 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, 286082 + ... + 286355.

It is an arithmetic number, because the mean of its divisors is an integer number (19749111).

Almost surely, 2^78423869 is an apocalyptic number.

It is an amenable number.

78423869 is a deficient number, since it is larger than the sum of its proper divisors (572575).

78423869 is a wasteful number, since it uses less digits than its factorization.

78423869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 572574.

The product of its digits is 580608, while the sum is 47.

The square root of 78423869 is about 8855.7252102806. The cubic root of 78423869 is about 428.0384223957.

It can be divided in two parts, 7842 and 3869, that added together give a palindrome (11711).

The spelling of 78423869 in words is "seventy-eight million, four hundred twenty-three thousand, eight hundred sixty-nine".