2021921 has 8 divisors (see below), whose sum is σ = 2216064. Its totient is φ = 1829520.

The previous prime is 2021891. The next prime is 2021927. The reversal of 2021921 is 1291202.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-2021921 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2021921.

It is not an unprimeable number, because it can be changed into a prime (2021927) 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 7 ways as a sum of consecutive naturals, for example, 4136 + ... + 4598.

It is an arithmetic number, because the mean of its divisors is an integer number (277008).

2^2021921 is an apocalyptic number.

It is an amenable number.

2021921 is a deficient number, since it is larger than the sum of its proper divisors (194143).

2021921 is a wasteful number, since it uses less digits than its factorization.

2021921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 871.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 2021921 is about 1421.9426852022. The cubic root of 2021921 is about 126.4507455608.

The spelling of 2021921 in words is "two million, twenty-one thousand, nine hundred twenty-one".