2021864 has 16 divisors (see below), whose sum is σ = 4082820. Its totient is φ = 933120.

The previous prime is 2021863. The next prime is 2021879. The reversal of 2021864 is 4681202.

It can be written as a sum of positive squares in 2 ways, for example, as 1800964 + 220900 = 1342^2 + 470^2 .

It is not an unprimeable number, because it can be changed into a prime (2021863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9617 + ... + 9824.

2^2021864 is an apocalyptic number.

It is an amenable number.

2021864 is an abundant number, since it is smaller than the sum of its proper divisors (2060956).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2021864 is a wasteful number, since it uses less digits than its factorization.

2021864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19460 (or 19456 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 2021864 is about 1421.9226420590. The cubic root of 2021864 is about 126.4495572915.

The spelling of 2021864 in words is "two million, twenty-one thousand, eight hundred sixty-four".