19991368 has 8 divisors (see below), whose sum is σ = 37483830. Its totient is φ = 9995680.

The previous prime is 19991357. The next prime is 19991381. The reversal of 19991368 is 86319991.

It can be written as a sum of positive squares in only one way, i.e., 19027044 + 964324 = 4362^2 + 982^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×19991368² = 799309589022848, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1249453 + ... + 1249468.

Almost surely, 2^19991368 is an apocalyptic number.

It is an amenable number.

19991368 is a deficient number, since it is larger than the sum of its proper divisors (17492462).

19991368 is a wasteful number, since it uses less digits than its factorization.

19991368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2498927 (or 2498923 counting only the distinct ones).

The product of its digits is 104976, while the sum is 46.

The square root of 19991368 is about 4471.1707639051. The cubic root of 19991368 is about 271.4027046185.

The spelling of 19991368 in words is "nineteen million, nine hundred ninety-one thousand, three hundred sixty-eight".