2109921 has 16 divisors (see below), whose sum is σ = 3250368. Its totient is φ = 1203200.

The previous prime is 2109911. The next prime is 2109941. The reversal of 2109921 is 1299012.

It is a cyclic number.

It is not a de Polignac number, because 2109921 - 2⁵ = 2109889 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2109891 and 2109900.

It is not an unprimeable number, because it can be changed into a prime (2109911) 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, 1320 + ... + 2441.

It is an arithmetic number, because the mean of its divisors is an integer number (203148).

2^2109921 is an apocalyptic number.

It is an amenable number.

2109921 is a deficient number, since it is larger than the sum of its proper divisors (1140447).

2109921 is a wasteful number, since it uses less digits than its factorization.

2109921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3792.

The product of its (nonzero) digits is 324, while the sum is 24.

The square root of 2109921 is about 1452.5567114574. The cubic root of 2109921 is about 128.2592604905.

The spelling of 2109921 in words is "two million, one hundred nine thousand, nine hundred twenty-one".