78409789 has 8 divisors (see below), whose sum is σ = 82620000. Its totient is φ = 74207952.

The previous prime is 78409787. The next prime is 78409813. The reversal of 78409789 is 98790487.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 78409789 - 2¹ = 78409787 is a prime.

It is a super-2 number, since 2×78409789² = 12296190022049042, 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 (78409787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29487 + ... + 32035.

It is an arithmetic number, because the mean of its divisors is an integer number (10327500).

Almost surely, 2^78409789 is an apocalyptic number.

It is an amenable number.

78409789 is a deficient number, since it is larger than the sum of its proper divisors (4210211).

78409789 is a wasteful number, since it uses less digits than its factorization.

78409789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4187.

The product of its (nonzero) digits is 1016064, while the sum is 52.

The square root of 78409789 is about 8854.9302086465. The cubic root of 78409789 is about 428.0128045926.

The spelling of 78409789 in words is "seventy-eight million, four hundred nine thousand, seven hundred eighty-nine".