2121609 has 16 divisors (see below), whose sum is σ = 3338240. Its totient is φ = 1172880.

The previous prime is 2121607. The next prime is 2121619. The reversal of 2121609 is 9061212.

It is not a de Polignac number, because 2121609 - 2¹ = 2121607 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Duffinian number.

It is a Curzon number.

2121609 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2121601) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 979 + ... + 2280.

It is an arithmetic number, because the mean of its divisors is an integer number (208640).

2^2121609 is an apocalyptic number.

It is an amenable number.

2121609 is a deficient number, since it is larger than the sum of its proper divisors (1216631).

2121609 is a wasteful number, since it uses less digits than its factorization.

2121609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3300.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 2121609 is about 1456.5744059265. The cubic root of 2121609 is about 128.4956571178.

The spelling of 2121609 in words is "two million, one hundred twenty-one thousand, six hundred nine".