1663689899 has 4 divisors (see below), whose sum is σ = 1664238600. Its totient is φ = 1663141200.

The previous prime is 1663689883. The next prime is 1663689901. The reversal of 1663689899 is 9989863661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9989863661 = 1789 ⋅5584049.

It is a cyclic number.

It is not a de Polignac number, because 1663689899 - 2⁴ = 1663689883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1663689869) 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, 269777 + ... + 275874.

It is an arithmetic number, because the mean of its divisors is an integer number (416059650).

Almost surely, 2^1663689899 is an apocalyptic number.

1663689899 is a deficient number, since it is larger than the sum of its proper divisors (548701).

1663689899 is an equidigital number, since it uses as much as digits as its factorization.

1663689899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 548700.

The product of its digits is 30233088, while the sum is 65.

The square root of 1663689899 is about 40788.3549435375. The cubic root of 1663689899 is about 1184.9248111717.

The spelling of 1663689899 in words is "one billion, six hundred sixty-three million, six hundred eighty-nine thousand, eight hundred ninety-nine".