78424069 has 4 divisors (see below), whose sum is σ = 78443596. Its totient is φ = 78404544.

The previous prime is 78424063. The next prime is 78424081. The reversal of 78424069 is 96042487.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 96042487 = 61 ⋅1574467.

It can be written as a sum of positive squares in 2 ways, for example, as 49533444 + 28890625 = 7038^2 + 5375^2 .

It is a cyclic number.

It is not a de Polignac number, because 78424069 - 2⁵ = 78424037 is a prime.

It is a super-2 number, since 2×78424069² = 12300669197033522, 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 (78424063) 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, 1284 + ... + 12589.

It is an arithmetic number, because the mean of its divisors is an integer number (19610899).

Almost surely, 2^78424069 is an apocalyptic number.

It is an amenable number.

78424069 is a deficient number, since it is larger than the sum of its proper divisors (19527).

78424069 is a wasteful number, since it uses less digits than its factorization.

78424069 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19526.

The product of its (nonzero) digits is 96768, while the sum is 40.

The square root of 78424069 is about 8855.7365024034. The cubic root of 78424069 is about 428.0387862629.

It can be divided in two parts, 7842 and 4069, that added together give a palindrome (11911).

The spelling of 78424069 in words is "seventy-eight million, four hundred twenty-four thousand, sixty-nine".