1663611399 has 16 divisors (see below), whose sum is σ = 2465263840. Its totient is φ = 1108779840.

The previous prime is 1663611359. The next prime is 1663611403. The reversal of 1663611399 is 9931163661.

It is a happy number.

1663611399 is a `hidden beast` number, since 1 + 6 + 636 + 1 + 1 + 3 + 9 + 9 = 666.

It is not a de Polignac number, because 1663611399 - 2¹¹ = 1663609351 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1663611349) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 153549 + ... + 164025.

It is an arithmetic number, because the mean of its divisors is an integer number (154078990).

Almost surely, 2^1663611399 is an apocalyptic number.

1663611399 is a deficient number, since it is larger than the sum of its proper divisors (801652441).

1663611399 is a wasteful number, since it uses less digits than its factorization.

1663611399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16367 (or 16361 counting only the distinct ones).

The product of its digits is 157464, while the sum is 45.

The square root of 1663611399 is about 40787.3926477288. The cubic root of 1663611399 is about 1184.9061742729.

The spelling of 1663611399 in words is "one billion, six hundred sixty-three million, six hundred eleven thousand, three hundred ninety-nine".