1661556589 has 8 divisors (see below), whose sum is σ = 2071551168. Its totient is φ = 1294719360.

The previous prime is 1661556587. The next prime is 1661556601. The reversal of 1661556589 is 9856551661.

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

It is not a de Polignac number, because 1661556589 - 2¹ = 1661556587 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661556587) 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, 10789252 + ... + 10789405.

It is an arithmetic number, because the mean of its divisors is an integer number (258943896).

Almost surely, 2^1661556589 is an apocalyptic number.

It is an amenable number.

1661556589 is a deficient number, since it is larger than the sum of its proper divisors (409994579).

1661556589 is a wasteful number, since it uses less digits than its factorization.

1661556589 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21578675.

The product of its digits is 1944000, while the sum is 52.

The square root of 1661556589 is about 40762.1955861065. The cubic root of 1661556589 is about 1184.4181275700.

The spelling of 1661556589 in words is "one billion, six hundred sixty-one million, five hundred fifty-six thousand, five hundred eighty-nine".