1988009 has 8 divisors (see below), whose sum is σ = 2041512. Its totient is φ = 1935360.

The previous prime is 1987991. The next prime is 1988011. The reversal of 1988009 is 9008891.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 105625 + 1882384 = 325^2 + 1372^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 1988009 - 2¹² = 1983913 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1988009.

It is not an unprimeable number, because it can be changed into a prime (1988089) 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, 8129 + ... + 8369.

It is an arithmetic number, because the mean of its divisors is an integer number (255189).

2^1988009 is an apocalyptic number.

It is an amenable number.

1988009 is a deficient number, since it is larger than the sum of its proper divisors (53503).

1988009 is a wasteful number, since it uses less digits than its factorization.

1988009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 427.

The product of its (nonzero) digits is 5184, while the sum is 35.

The square root of 1988009 is about 1409.9677301272. The cubic root of 1988009 is about 125.7398048721.

The spelling of 1988009 in words is "one million, nine hundred eighty-eight thousand, nine".