2021688 has 48 divisors (see below), whose sum is σ = 5611320. Its totient is φ = 657216.

The previous prime is 2021671. The next prime is 2021693. The reversal of 2021688 is 8861202.

2021688 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2770 + ... + 3422.

2^2021688 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2021688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2805660).

2021688 is an abundant number, since it is smaller than the sum of its proper divisors (3589632).

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

2021688 is a wasteful number, since it uses less digits than its factorization.

2021688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708 (or 701 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 2021688 is about 1421.8607526759. The cubic root of 2021688 is about 126.4458881084.

Multiplying 2021688 by its sum of digits (27), we get a triangular number (54585576 = T₁₀₄₄₈).

The spelling of 2021688 in words is "two million, twenty-one thousand, six hundred eighty-eight".