2161566 has 40 divisors (see below), whose sum is σ = 5288184. Its totient is φ = 654480.

The previous prime is 2161553. The next prime is 2161571. The reversal of 2161566 is 6651612.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1176 + ... + 2388.

2^2161566 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2161566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2644092).

2161566 is an abundant number, since it is smaller than the sum of its proper divisors (3126618).

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

2161566 is a wasteful number, since it uses less digits than its factorization.

2161566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1238 (or 1229 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 2161566 is about 1470.2265131605. The cubic root of 2161566 is about 129.2973131585.

The spelling of 2161566 in words is "two million, one hundred sixty-one thousand, five hundred sixty-six".