99899978 has 16 divisors (see below), whose sum is σ = 151517184. Its totient is φ = 49397040.

The previous prime is 99899959. The next prime is 99899981. The reversal of 99899978 is 87999899.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 137051 + ... + 137777.

It is an arithmetic number, because the mean of its divisors is an integer number (9469824).

Almost surely, 2^99899978 is an apocalyptic number.

99899978 is a deficient number, since it is larger than the sum of its proper divisors (51617206).

99899978 is a wasteful number, since it uses less digits than its factorization.

99899978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1397.

The product of its digits is 26453952, while the sum is 68.

The square root of 99899978 is about 9994.9976488241. The cubic root of 99899978 is about 464.0040780706.

The spelling of 99899978 in words is "ninety-nine million, eight hundred ninety-nine thousand, nine hundred seventy-eight".