2142809 has 4 divisors (see below), whose sum is σ = 2154960. Its totient is φ = 2130660.

The previous prime is 2142793. The next prime is 2142823. The reversal of 2142809 is 9082412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2142809 - 2⁴ = 2142793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2141809) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5807 + ... + 6164.

It is an arithmetic number, because the mean of its divisors is an integer number (538740).

2^2142809 is an apocalyptic number.

It is an amenable number.

2142809 is a deficient number, since it is larger than the sum of its proper divisors (12151).

2142809 is a wasteful number, since it uses less digits than its factorization.

2142809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12150.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 2142809 is about 1463.8336654142. The cubic root of 2142809 is about 128.9222334402.

The spelling of 2142809 in words is "two million, one hundred forty-two thousand, eight hundred nine".