2101905 has 24 divisors (see below), whose sum is σ = 3924648. Its totient is φ = 1034496.

The previous prime is 2101903. The next prime is 2101907. The reversal of 2101905 is 5091012.

It is an interprime number because it is at equal distance from previous prime (2101903) and next prime (2101907).

It can be written as a sum of positive squares in 4 ways, for example, as 2304 + 2099601 = 48^2 + 1449^2 .

It is not a de Polignac number, because 2101905 - 2¹ = 2101903 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2101903) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1212 + ... + 2381.

It is an arithmetic number, because the mean of its divisors is an integer number (163527).

2^2101905 is an apocalyptic number.

It is an amenable number.

2101905 is a deficient number, since it is larger than the sum of its proper divisors (1822743).

2101905 is a wasteful number, since it uses less digits than its factorization.

2101905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3617 (or 3614 counting only the distinct ones).

The product of its (nonzero) digits is 90, while the sum is 18.

The square root of 2101905 is about 1449.7948130684. The cubic root of 2101905 is about 128.0966270705.

Adding to 2101905 its reverse (5091012), we get a palindrome (7192917).

The spelling of 2101905 in words is "two million, one hundred one thousand, nine hundred five".