2129909 has 4 divisors (see below), whose sum is σ = 2181900. Its totient is φ = 2077920.

The previous prime is 2129903. The next prime is 2129951. The reversal of 2129909 is 9099212.

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

It can be written as a sum of positive squares in 2 ways, for example, as 253009 + 1876900 = 503^2 + 1370^2 .

It is a cyclic number.

It is not a de Polignac number, because 2129909 - 2¹² = 2125813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2129903) 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, 25934 + ... + 26015.

It is an arithmetic number, because the mean of its divisors is an integer number (545475).

2^2129909 is an apocalyptic number.

It is an amenable number.

2129909 is a deficient number, since it is larger than the sum of its proper divisors (51991).

2129909 is an equidigital number, since it uses as much as digits as its factorization.

2129909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51990.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 2129909 is about 1459.4207755134. The cubic root of 2129909 is about 128.6630027802.

The spelling of 2129909 in words is "two million, one hundred twenty-nine thousand, nine hundred nine".