2161905 has 16 divisors (see below), whose sum is σ = 3495744. Its totient is φ = 1140800.

The previous prime is 2161903. The next prime is 2161919. The reversal of 2161905 is 5091612.

It is not a de Polignac number, because 2161905 - 2¹ = 2161903 is a prime.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (2161903) 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, 802 + ... + 2228.

It is an arithmetic number, because the mean of its divisors is an integer number (218484).

2^2161905 is an apocalyptic number.

It is an amenable number.

2161905 is a deficient number, since it is larger than the sum of its proper divisors (1333839).

2161905 is a wasteful number, since it uses less digits than its factorization.

2161905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1536.

The product of its (nonzero) digits is 540, while the sum is 24.

The square root of 2161905 is about 1470.3417969982. The cubic root of 2161905 is about 129.3040720697.

The spelling of 2161905 in words is "two million, one hundred sixty-one thousand, nine hundred five".