2021687 has 4 divisors (see below), whose sum is σ = 2027040. Its totient is φ = 2016336.

The previous prime is 2021671. The next prime is 2021693. The reversal of 2021687 is 7861202.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7861202 = 2 ⋅3930601.

It is a cyclic number.

It is not a de Polignac number, because 2021687 - 2⁴ = 2021671 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2021627) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2063 + ... + 2880.

It is an arithmetic number, because the mean of its divisors is an integer number (506760).

2^2021687 is an apocalyptic number.

2021687 is a deficient number, since it is larger than the sum of its proper divisors (5353).

2021687 is an equidigital number, since it uses as much as digits as its factorization.

2021687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5352.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 2021687 is about 1421.8604010240. The cubic root of 2021687 is about 126.4458672601.

Adding to 2021687 its reverse (7861202), we get a palindrome (9882889).

The spelling of 2021687 in words is "two million, twenty-one thousand, six hundred eighty-seven".