1866021 has 8 divisors (see below), whose sum is σ = 2555424. Its totient is φ = 1210320.

The previous prime is 1866019. The next prime is 1866031. The reversal of 1866021 is 1206681.

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

It is not a de Polignac number, because 1866021 - 2¹ = 1866019 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1865982 and 1866000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1866001) 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, 8295 + ... + 8516.

It is an arithmetic number, because the mean of its divisors is an integer number (319428).

2^1866021 is an apocalyptic number.

It is an amenable number.

1866021 is a deficient number, since it is larger than the sum of its proper divisors (689403).

1866021 is a wasteful number, since it uses less digits than its factorization.

1866021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16851.

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 1866021 is about 1366.0237918865. The cubic root of 1866021 is about 123.1134520679.

It can be divided in two parts, 18660 and 21, that added together give a palindrome (18681).

The spelling of 1866021 in words is "one million, eight hundred sixty-six thousand, twenty-one".