99979989 has 8 divisors (see below), whose sum is σ = 133432992. Its totient is φ = 66590160.

The previous prime is 99979981. The next prime is 99979993. The reversal of 99979989 is 98997999.

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

It is not a de Polignac number, because 99979989 - 2³ = 99979981 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99979981) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11967 + ... + 18524.

It is an arithmetic number, because the mean of its divisors is an integer number (16679124).

Almost surely, 2^99979989 is an apocalyptic number.

It is an amenable number.

99979989 is a deficient number, since it is larger than the sum of its proper divisors (33453003).

99979989 is a wasteful number, since it uses less digits than its factorization.

99979989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31587.

The product of its digits is 29760696, while the sum is 69.

The square root of 99979989 is about 9998.9993999400. Note that the first 3 decimals coincide. The cubic root of 99979989 is about 464.1279203511.

The spelling of 99979989 in words is "ninety-nine million, nine hundred seventy-nine thousand, nine hundred eighty-nine".