2159866 has 4 divisors (see below), whose sum is σ = 3239802. Its totient is φ = 1079932.

The previous prime is 2159831. The next prime is 2159881. The reversal of 2159866 is 6689512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 2019241 + 140625 = 1421^2 + 375^2 .

It is a super-2 number, since 2×2159866² = 9330042275912, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 539965 + ... + 539968.

2^2159866 is an apocalyptic number.

2159866 is a deficient number, since it is larger than the sum of its proper divisors (1079936).

2159866 is a wasteful number, since it uses less digits than its factorization.

2159866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1079935.

The product of its digits is 25920, while the sum is 37.

The square root of 2159866 is about 1469.6482572371. The cubic root of 2159866 is about 129.2634082517.

It can be divided in two parts, 2159 and 866, that added together give a square (3025 = 55²).

The spelling of 2159866 in words is "two million, one hundred fifty-nine thousand, eight hundred sixty-six".