1661856 has 48 divisors (see below), whose sum is σ = 4987584. Its totient is φ = 474624.

The previous prime is 1661851. The next prime is 1661857. The reversal of 1661856 is 6581661.

It is a tau number, because it is divible by the number of its divisors (48).

It is not an unprimeable number, because it can be changed into a prime (1661851) 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, 565 + ... + 1908.

It is an arithmetic number, because the mean of its divisors is an integer number (103908).

2^1661856 is an apocalyptic number.

1661856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1661856 is an abundant number, since it is smaller than the sum of its proper divisors (3325728).

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

1661856 is a wasteful number, since it uses less digits than its factorization.

1661856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2493 (or 2485 counting only the distinct ones).

The product of its digits is 8640, while the sum is 33.

The square root of 1661856 is about 1289.1299391450. The cubic root of 1661856 is about 118.4489266990.

The spelling of 1661856 in words is "one million, six hundred sixty-one thousand, eight hundred fifty-six".