99778 has 8 divisors (see below), whose sum is σ = 171072. Its totient is φ = 42756.

The previous prime is 99767. The next prime is 99787. The reversal of 99778 is 87799.

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

It is a self number, because there is not a number n which added to its sum of digits gives 99778.

It is an unprimeable number.

99778 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3550 + ... + 3577.

It is an arithmetic number, because the mean of its divisors is an integer number (21384).

2⁹⁹⁷⁷⁸ is an apocalyptic number.

99778 is a deficient number, since it is larger than the sum of its proper divisors (71294).

99778 is a wasteful number, since it uses less digits than its factorization.

99778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7136.

The product of its digits is 31752, while the sum is 40.

The square root of 99778 is about 315.8765581679. The cubic root of 99778 is about 46.3815151300.

The spelling of 99778 in words is "ninety-nine thousand, seven hundred seventy-eight".