2181908 has 6 divisors (see below), whose sum is σ = 3818346. Its totient is φ = 1090952.

The previous prime is 2181889. The next prime is 2181919. The reversal of 2181908 is 8091812.

It can be written as a sum of positive squares in only one way, i.e., 1898884 + 283024 = 1378^2 + 532^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 272735 + ... + 272742.

It is an arithmetic number, because the mean of its divisors is an integer number (636391).

2^2181908 is an apocalyptic number.

It is an amenable number.

2181908 is a deficient number, since it is larger than the sum of its proper divisors (1636438).

2181908 is a wasteful number, since it uses less digits than its factorization.

2181908 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 545481 (or 545479 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 29.

The square root of 2181908 is about 1477.1282950374. The cubic root of 2181908 is about 129.7016431955.

The spelling of 2181908 in words is "two million, one hundred eighty-one thousand, nine hundred eight".