78399899 has 4 divisors (see below), whose sum is σ = 80928960. Its totient is φ = 75870840.

The previous prime is 78399889. The next prime is 78399917. The reversal of 78399899 is 99899387.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 78399899 - 2¹² = 78395803 is a prime.

It is a super-2 number, since 2×78399899² = 12293088326420402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78399809) 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, 1264484 + ... + 1264545.

It is an arithmetic number, because the mean of its divisors is an integer number (20232240).

Almost surely, 2^78399899 is an apocalyptic number.

78399899 is a deficient number, since it is larger than the sum of its proper divisors (2529061).

78399899 is a wasteful number, since it uses less digits than its factorization.

78399899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2529060.

The product of its digits is 8817984, while the sum is 62.

The square root of 78399899 is about 8854.3717450760. The cubic root of 78399899 is about 427.9948084356.

The spelling of 78399899 in words is "seventy-eight million, three hundred ninety-nine thousand, eight hundred ninety-nine".