1661289 has 16 divisors (see below), whose sum is σ = 2549760. Its totient is φ = 942480.

The previous prime is 1661281. The next prime is 1661293. The reversal of 1661289 is 9821661.

It is not a de Polignac number, because 1661289 - 2³ = 1661281 is a prime.

It is a super-2 number, since 2×1661289² = 5519762283042, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1661281) 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 15 ways as a sum of consecutive naturals, for example, 4854 + ... + 5184.

It is an arithmetic number, because the mean of its divisors is an integer number (159360).

2^1661289 is an apocalyptic number.

It is an amenable number.

1661289 is a deficient number, since it is larger than the sum of its proper divisors (888471).

1661289 is a wasteful number, since it uses less digits than its factorization.

1661289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 580.

The product of its digits is 5184, while the sum is 33.

The square root of 1661289 is about 1288.9100046163. The cubic root of 1661289 is about 118.4354541757.

The spelling of 1661289 in words is "one million, six hundred sixty-one thousand, two hundred eighty-nine".