1866491 has 4 divisors (see below), whose sum is σ = 2036184. Its totient is φ = 1696800.

The previous prime is 1866467. The next prime is 1866499. The reversal of 1866491 is 1946681.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1866491 - 2¹⁰ = 1865467 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1866499) 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, 84830 + ... + 84851.

It is an arithmetic number, because the mean of its divisors is an integer number (509046).

2^1866491 is an apocalyptic number.

1866491 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1866491 is a deficient number, since it is larger than the sum of its proper divisors (169693).

1866491 is a wasteful number, since it uses less digits than its factorization.

1866491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169692.

The product of its digits is 10368, while the sum is 35.

The square root of 1866491 is about 1366.1958131981. The cubic root of 1866491 is about 123.1237875116.

The spelling of 1866491 in words is "one million, eight hundred sixty-six thousand, four hundred ninety-one".