2156609 has 12 divisors (see below), whose sum is σ = 2670336. Its totient is φ = 1705392.

The previous prime is 2156599. The next prime is 2156617. The reversal of 2156609 is 9066512.

It is a de Polignac number, because none of the positive numbers 2^k-2156609 is a prime.

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a Curzon number.

It is a zygodrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2156629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 272 + ... + 2094.

It is an arithmetic number, because the mean of its divisors is an integer number (222528).

2^2156609 is an apocalyptic number.

It is an amenable number.

2156609 is a deficient number, since it is larger than the sum of its proper divisors (513727).

2156609 is a wasteful number, since it uses less digits than its factorization.

2156609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1856 (or 1843 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 2156609 is about 1468.5397509090. The cubic root of 2156609 is about 129.1984007125.

Subtracting 2156609 from its reverse (9066512), we obtain a triangular number (6909903 = T₃₇₁₇).

The spelling of 2156609 in words is "two million, one hundred fifty-six thousand, six hundred nine".