1661556 has 24 divisors (see below), whose sum is σ = 4175584. Its totient is φ = 511200.

The previous prime is 1661549. The next prime is 1661557. The reversal of 1661556 is 6551661.

It is a super-2 number, since 2×1661556² = 5521536682272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661557) 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, 5170 + ... + 5481.

2^1661556 is an apocalyptic number.

It is an amenable number.

1661556 is an abundant number, since it is smaller than the sum of its proper divisors (2514028).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1661556 is a wasteful number, since it uses less digits than its factorization.

1661556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10671 (or 10669 counting only the distinct ones).

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

The square root of 1661556 is about 1289.0135763443. The cubic root of 1661556 is about 118.4417987616.

The spelling of 1661556 in words is "one million, six hundred sixty-one thousand, five hundred fifty-six".