1999663 has 4 divisors (see below), whose sum is σ = 2007160. Its totient is φ = 1992168.

The previous prime is 1999661. The next prime is 1999667. The reversal of 1999663 is 3669991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3669991 = 13 ⋅282307.

It is a cyclic number.

It is not a de Polignac number, because 1999663 - 2¹ = 1999661 is a prime.

It is a super-2 number, since 2×1999663² = 7997304227138, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1999661) 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, 3333 + ... + 3886.

It is an arithmetic number, because the mean of its divisors is an integer number (501790).

2^1999663 is an apocalyptic number.

1999663 is a deficient number, since it is larger than the sum of its proper divisors (7497).

1999663 is an equidigital number, since it uses as much as digits as its factorization.

1999663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7496.

The product of its digits is 78732, while the sum is 43.

The square root of 1999663 is about 1414.0944098610. The cubic root of 1999663 is about 125.9850280354.

It can be divided in two parts, 1999 and 663, that added together give a palindrome (2662).

The spelling of 1999663 in words is "one million, nine hundred ninety-nine thousand, six hundred sixty-three".