78042309 has 16 divisors (see below), whose sum is σ = 106275840. Its totient is φ = 50926320.

The previous prime is 78042301. The next prime is 78042317. The reversal of 78042309 is 90324087.

It is an interprime number because it is at equal distance from previous prime (78042301) and next prime (78042317).

It is not a de Polignac number, because 78042309 - 2³ = 78042301 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 78042309.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78042301) 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 15 ways as a sum of consecutive naturals, for example, 47154 + ... + 48780.

It is an arithmetic number, because the mean of its divisors is an integer number (6642240).

Almost surely, 2^78042309 is an apocalyptic number.

It is an amenable number.

78042309 is a deficient number, since it is larger than the sum of its proper divisors (28233531).

78042309 is a wasteful number, since it uses less digits than its factorization.

78042309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1960.

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 78042309 is about 8834.1558170546. The cubic root of 78042309 is about 427.3431071617.

The spelling of 78042309 in words is "seventy-eight million, forty-two thousand, three hundred nine".