1655561 has 4 divisors (see below), whose sum is σ = 1686852. Its totient is φ = 1624272.

The previous prime is 1655557. The next prime is 1655569.

1655561 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1336336 + 319225 = 1156^2 + 565^2 .

It is a cyclic number.

It is not a de Polignac number, because 1655561 - 2² = 1655557 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1655569) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15566 + ... + 15671.

It is an arithmetic number, because the mean of its divisors is an integer number (421713).

2^1655561 is an apocalyptic number.

It is an amenable number.

1655561 is a deficient number, since it is larger than the sum of its proper divisors (31291).

1655561 is an equidigital number, since it uses as much as digits as its factorization.

1655561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31290.

The product of its digits is 4500, while the sum is 29.

The square root of 1655561 is about 1286.6860533945. The cubic root of 1655561 is about 118.2991785754.

The spelling of 1655561 in words is "one million, six hundred fifty-five thousand, five hundred sixty-one".