78423920 has 20 divisors (see below), whose sum is σ = 182335800. Its totient is φ = 31369536.

The previous prime is 78423913. The next prime is 78423923. The reversal of 78423920 is 2932487.

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×78423920² = 12300622456332800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78423923) 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 3 ways as a sum of consecutive naturals, for example, 490070 + ... + 490229.

It is an arithmetic number, because the mean of its divisors is an integer number (9116790).

Almost surely, 2^78423920 is an apocalyptic number.

It is an amenable number.

78423920 is an abundant number, since it is smaller than the sum of its proper divisors (103911880).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

78423920 is a wasteful number, since it uses less digits than its factorization.

78423920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 980312 (or 980306 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 35.

The square root of 78423920 is about 8855.7280897733. The cubic root of 78423920 is about 428.0385151819.

The spelling of 78423920 in words is "seventy-eight million, four hundred twenty-three thousand, nine hundred twenty".