1555866 has 48 divisors (see below), whose sum is σ = 3723720. Its totient is φ = 466560.

The previous prime is 1555861. The next prime is 1555901. The reversal of 1555866 is 6685551.

It can be written as a sum of positive squares in 4 ways, for example, as 772641 + 783225 = 879^2 + 885^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1555866.

It is not an unprimeable number, because it can be changed into a prime (1555861) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14220 + ... + 14328.

2^1555866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1555866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1861860).

1555866 is an abundant number, since it is smaller than the sum of its proper divisors (2167854).

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

1555866 is a wasteful number, since it uses less digits than its factorization.

1555866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191 (or 188 counting only the distinct ones).

The product of its digits is 36000, while the sum is 36.

The square root of 1555866 is about 1247.3435773675. The cubic root of 1555866 is about 115.8752622680.

The spelling of 1555866 in words is "one million, five hundred fifty-five thousand, eight hundred sixty-six".