2161864 has 16 divisors (see below), whose sum is σ = 4078620. Its totient is φ = 1074240.

The previous prime is 2161853. The next prime is 2161871. The reversal of 2161864 is 4681612.

It can be written as a sum of positive squares in 2 ways, for example, as 2125764 + 36100 = 1458^2 + 190^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 702 + ... + 2194.

2^2161864 is an apocalyptic number.

It is an amenable number.

2161864 is a deficient number, since it is larger than the sum of its proper divisors (1916756).

2161864 is a wasteful number, since it uses less digits than its factorization.

2161864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1680 (or 1676 counting only the distinct ones).

The product of its digits is 2304, while the sum is 28.

The square root of 2161864 is about 1470.3278545957. The cubic root of 2161864 is about 129.3032546578.

It can be divided in two parts, 2161 and 864, that added together give a square (3025 = 55²).

The spelling of 2161864 in words is "two million, one hundred sixty-one thousand, eight hundred sixty-four".