1663899 has 4 divisors (see below), whose sum is σ = 2218536. Its totient is φ = 1109264.

The previous prime is 1663891. The next prime is 1663913. The reversal of 1663899 is 9983661.

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 1663899 - 2³ = 1663891 is a prime.

It is a D-number.

It is a self number, because there is not a number n which added to its sum of digits gives 1663899.

It is not an unprimeable number, because it can be changed into a prime (1663891) 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, 277314 + ... + 277319.

It is an arithmetic number, because the mean of its divisors is an integer number (554634).

2^1663899 is an apocalyptic number.

1663899 is a deficient number, since it is larger than the sum of its proper divisors (554637).

1663899 is an equidigital number, since it uses as much as digits as its factorization.

1663899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 554636.

The product of its digits is 69984, while the sum is 42.

The square root of 1663899 is about 1289.9220906706. The cubic root of 1663899 is about 118.4974451549.

The spelling of 1663899 in words is "one million, six hundred sixty-three thousand, eight hundred ninety-nine".