1801989 has 12 divisors (see below), whose sum is σ = 2974816. Its totient is φ = 1029672.

The previous prime is 1801967. The next prime is 1801997. The reversal of 1801989 is 9891081.

It is not a de Polignac number, because 1801989 - 2⁸ = 1801733 is a prime.

It is a super-2 number, since 2×1801989² = 6494328712242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1801489) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14239 + ... + 14364.

2^1801989 is an apocalyptic number.

It is an amenable number.

1801989 is a deficient number, since it is larger than the sum of its proper divisors (1172827).

1801989 is a wasteful number, since it uses less digits than its factorization.

1801989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28616 (or 28613 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 36.

The square root of 1801989 is about 1342.3818383754. The cubic root of 1801989 is about 121.6888289729.

The spelling of 1801989 in words is "one million, eight hundred one thousand, nine hundred eighty-nine".