1990989 has 72 divisors (see below), whose sum is σ = 4110912. Its totient is φ = 898560.

The previous prime is 1990987. The next prime is 1991027. The reversal of 1990989 is 9890991.

It is not a de Polignac number, because 1990989 - 2¹ = 1990987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1990981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 117109 + ... + 117125.

It is an arithmetic number, because the mean of its divisors is an integer number (57096).

2^1990989 is an apocalyptic number.

It is an amenable number.

1990989 is an abundant number, since it is smaller than the sum of its proper divisors (2119923).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1990989 is a wasteful number, since it uses less digits than its factorization.

1990989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67 (or 51 counting only the distinct ones).

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

The square root of 1990989 is about 1411.0240961798. The cubic root of 1990989 is about 125.8026009574.

The spelling of 1990989 in words is "one million, nine hundred ninety thousand, nine hundred eighty-nine".