1866641 has 4 divisors (see below), whose sum is σ = 2133312. Its totient is φ = 1599972.

The previous prime is 1866637. The next prime is 1866649. The reversal of 1866641 is 1466681.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1466681 = 59 ⋅24859.

It is a cyclic number.

It is not a de Polignac number, because 1866641 - 2² = 1866637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1866598 and 1866607.

It is not an unprimeable number, because it can be changed into a prime (1866649) 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, 133325 + ... + 133338.

It is an arithmetic number, because the mean of its divisors is an integer number (533328).

2^1866641 is an apocalyptic number.

It is an amenable number.

1866641 is a deficient number, since it is larger than the sum of its proper divisors (266671).

1866641 is an equidigital number, since it uses as much as digits as its factorization.

1866641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266670.

The product of its digits is 6912, while the sum is 32.

The square root of 1866641 is about 1366.2507090575. The cubic root of 1866641 is about 123.1270856922.

The spelling of 1866641 in words is "one million, eight hundred sixty-six thousand, six hundred forty-one".