19999808 has 28 divisors (see below), whose sum is σ = 39994332. Its totient is φ = 9922560.

The previous prime is 19999789. The next prime is 19999817. The reversal of 19999808 is 80899991.

It can be written as a sum of positive squares in 2 ways, for example, as 11888704 + 8111104 = 3448^2 + 2848^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 19999808.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7628 + ... + 9908.

It is an arithmetic number, because the mean of its divisors is an integer number (1428369).

Almost surely, 2^19999808 is an apocalyptic number.

It is an amenable number.

19999808 is a deficient number, since it is larger than the sum of its proper divisors (19994524).

19999808 is a wasteful number, since it uses less digits than its factorization.

19999808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2430 (or 2420 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 53.

The square root of 19999808 is about 4472.1144886955. The cubic root of 19999808 is about 271.4408930431.

The spelling of 19999808 in words is "nineteen million, nine hundred ninety-nine thousand, eight hundred eight".