1556661 has 8 divisors (see below), whose sum is σ = 2091040. Its totient is φ = 1030032.

The previous prime is 1556657. The next prime is 1556669. The reversal of 1556661 is 1666551.

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

It is not a de Polignac number, because 1556661 - 2² = 1556657 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 (1556669) 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 7 ways as a sum of consecutive naturals, for example, 1450 + ... + 2283.

It is an arithmetic number, because the mean of its divisors is an integer number (261380).

2^1556661 is an apocalyptic number.

It is an amenable number.

1556661 is a deficient number, since it is larger than the sum of its proper divisors (534379).

1556661 is a wasteful number, since it uses less digits than its factorization.

1556661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3875.

The product of its digits is 5400, while the sum is 30.

The square root of 1556661 is about 1247.6622139025. The cubic root of 1556661 is about 115.8949951472.

The spelling of 1556661 in words is "one million, five hundred fifty-six thousand, six hundred sixty-one".