19999872 has 96 divisors (see below), whose sum is σ = 59776080. Its totient is φ = 6656256.

The previous prime is 19999843. The next prime is 19999873. The reversal of 19999872 is 27899991.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (54).

Its product of digits (734832) is a multiple of the sum of its prime divisors (648).

It is not an unprimeable number, because it can be changed into a prime (19999873) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 30783 + ... + 31425.

Almost surely, 2^19999872 is an apocalyptic number.

19999872 is a gapful number since it is divisible by the number (12) 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 19999872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29888040).

19999872 is an abundant number, since it is smaller than the sum of its proper divisors (39776208).

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

19999872 is an frugal number, since it uses more digits than its factorization.

19999872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 672 (or 648 counting only the distinct ones).

The product of its digits is 734832, while the sum is 54.

The square root of 19999872 is about 4472.1216441416. The cubic root of 19999872 is about 271.4411825825.

The spelling of 19999872 in words is "nineteen million, nine hundred ninety-nine thousand, eight hundred seventy-two".