1998909 has 24 divisors (see below), whose sum is σ = 3211104. Its totient is φ = 1188000.

The previous prime is 1998881. The next prime is 1998917. The reversal of 1998909 is 9098991.

It is not a de Polignac number, because 1998909 - 2⁹ = 1998397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998949) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5874 + ... + 6204.

It is an arithmetic number, because the mean of its divisors is an integer number (133796).

2^1998909 is an apocalyptic number.

It is an amenable number.

1998909 is a deficient number, since it is larger than the sum of its proper divisors (1212195).

1998909 is a wasteful number, since it uses less digits than its factorization.

1998909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409 (or 406 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 45.

The square root of 1998909 is about 1413.8277830061. The cubic root of 1998909 is about 125.9691912581.

The spelling of 1998909 in words is "one million, nine hundred ninety-eight thousand, nine hundred nine".