1663859 has 4 divisors (see below), whose sum is σ = 1692120. Its totient is φ = 1635600.

The previous prime is 1663813. The next prime is 1663861. The reversal of 1663859 is 9583661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9583661 = 239 ⋅40099.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1663859 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1623859) 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, 14042 + ... + 14159.

It is an arithmetic number, because the mean of its divisors is an integer number (423030).

2^1663859 is an apocalyptic number.

1663859 is a deficient number, since it is larger than the sum of its proper divisors (28261).

1663859 is an equidigital number, since it uses as much as digits as its factorization.

1663859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28260.

The product of its digits is 38880, while the sum is 38.

The square root of 1663859 is about 1289.9065857650. The cubic root of 1663859 is about 118.4964955909.

The spelling of 1663859 in words is "one million, six hundred sixty-three thousand, eight hundred fifty-nine".