78399361 has 4 divisors (see below), whose sum is σ = 78417072. Its totient is φ = 78381652.

The previous prime is 78399353. The next prime is 78399379. The reversal of 78399361 is 16399387.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 16399387 = 149 ⋅110063.

It is a cyclic number.

It is not a de Polignac number, because 78399361 - 2³ = 78399353 is a prime.

It is a super-2 number, since 2×78399361² = 12292919610416642, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78399311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4266 + ... + 13228.

It is an arithmetic number, because the mean of its divisors is an integer number (19604268).

Almost surely, 2^78399361 is an apocalyptic number.

It is an amenable number.

78399361 is a deficient number, since it is larger than the sum of its proper divisors (17711).

78399361 is an equidigital number, since it uses as much as digits as its factorization.

78399361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17710.

The product of its digits is 244944, while the sum is 46.

The square root of 78399361 is about 8854.3413645511. The cubic root of 78399361 is about 427.9938294304.

The spelling of 78399361 in words is "seventy-eight million, three hundred ninety-nine thousand, three hundred sixty-one".