99997989 has 16 divisors (see below), whose sum is σ = 164099712. Its totient is φ = 52746048.

The previous prime is 99997981. The next prime is 99998021. The reversal of 99997989 is 98979999.

It is not a de Polignac number, because 99997989 - 2³ = 99997981 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99997981) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 182874 + ... + 183419.

It is an arithmetic number, because the mean of its divisors is an integer number (10256232).

Almost surely, 2^99997989 is an apocalyptic number.

It is an amenable number.

99997989 is a deficient number, since it is larger than the sum of its proper divisors (64101723).

99997989 is a wasteful number, since it uses less digits than its factorization.

99997989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 366316.

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

The square root of 99997989 is about 9999.8994494945. The cubic root of 99997989 is about 464.1557719287.

The spelling of 99997989 in words is "ninety-nine million, nine hundred ninety-seven thousand, nine hundred eighty-nine".