19991268 has 72 divisors (see below), whose sum is σ = 58050720. Its totient is φ = 5736960.

The previous prime is 19991267. The next prime is 19991299. The reversal of 19991268 is 86219991.

It is not an unprimeable number, because it can be changed into a prime (19991267) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6196 + ... + 8852.

It is an arithmetic number, because the mean of its divisors is an integer number (806260).

Almost surely, 2^19991268 is an apocalyptic number.

19991268 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19991268, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29025360).

19991268 is an abundant number, since it is smaller than the sum of its proper divisors (38059452).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19991268 is a wasteful number, since it uses less digits than its factorization.

19991268 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2697 (or 2692 counting only the distinct ones).

The product of its digits is 69984, while the sum is 45.

The square root of 19991268 is about 4471.1595811378. The cubic root of 19991268 is about 271.4022520846.

The spelling of 19991268 in words is "nineteen million, nine hundred ninety-one thousand, two hundred sixty-eight".