2009851 has 4 divisors (see below), whose sum is σ = 2028400. Its totient is φ = 1991304.

The previous prime is 2009831. The next prime is 2009857. The reversal of 2009851 is 1589002.

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

It is a cyclic number.

It is not a de Polignac number, because 2009851 - 2⁹ = 2009339 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2009857) 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, 9111 + ... + 9328.

It is an arithmetic number, because the mean of its divisors is an integer number (507100).

2^2009851 is an apocalyptic number.

2009851 is a deficient number, since it is larger than the sum of its proper divisors (18549).

2009851 is a wasteful number, since it uses less digits than its factorization.

2009851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18548.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 2009851 is about 1417.6921386535. The cubic root of 2009851 is about 126.1986243271.

The spelling of 2009851 in words is "two million, nine thousand, eight hundred fifty-one".