1866405 has 8 divisors (see below), whose sum is σ = 2986272. Its totient is φ = 995408.

The previous prime is 1866373. The next prime is 1866409. The reversal of 1866405 is 5046681.

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

It is a cyclic number.

It is not a de Polignac number, because 1866405 - 2⁵ = 1866373 is a prime.

1866405 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1866409) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62199 + ... + 62228.

It is an arithmetic number, because the mean of its divisors is an integer number (373284).

2^1866405 is an apocalyptic number.

1866405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1866405 is a deficient number, since it is larger than the sum of its proper divisors (1119867).

1866405 is a wasteful number, since it uses less digits than its factorization.

1866405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124435.

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 1866405 is about 1366.1643385772. The cubic root of 1866405 is about 123.1218964750.

The spelling of 1866405 in words is "one million, eight hundred sixty-six thousand, four hundred five".