2143809 has 6 divisors (see below), whose sum is σ = 3096626. Its totient is φ = 1429200.

The previous prime is 2143793. The next prime is 2143829. The reversal of 2143809 is 9083412.

2143809 is nontrivially palindromic in base 8.

It can be written as a sum of positive squares in only one way, i.e., 1199025 + 944784 = 1095^2 + 972^2 .

It is not a de Polignac number, because 2143809 - 2⁴ = 2143793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2143829) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 119092 + ... + 119109.

2^2143809 is an apocalyptic number.

It is an amenable number.

2143809 is a deficient number, since it is larger than the sum of its proper divisors (952817).

2143809 is a wasteful number, since it uses less digits than its factorization.

2143809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238207 (or 238204 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 2143809 is about 1464.1751944354. The cubic root of 2143809 is about 128.9422853415.

The spelling of 2143809 in words is "two million, one hundred forty-three thousand, eight hundred nine".