2151909 has 12 divisors (see below), whose sum is σ = 3127852. Its totient is φ = 1425600.

The previous prime is 2151899. The next prime is 2151917. The reversal of 2151909 is 9091512.

It is a happy number.

2151909 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 893025 + 1258884 = 945^2 + 1122^2 .

It is not a de Polignac number, because 2151909 - 2⁷ = 2151781 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 (2151509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 969 + ... + 2289.

2^2151909 is an apocalyptic number.

It is an amenable number.

2151909 is a deficient number, since it is larger than the sum of its proper divisors (975943).

2151909 is a wasteful number, since it uses less digits than its factorization.

2151909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1508 (or 1505 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 27.

The square root of 2151909 is about 1466.9386490239. The cubic root of 2151909 is about 129.1044763863.

The spelling of 2151909 in words is "two million, one hundred fifty-one thousand, nine hundred nine".