19999728 has 60 divisors (see below), whose sum is σ = 63970608. Its totient is φ = 5713920.

The previous prime is 19999697. The next prime is 19999729. The reversal of 19999728 is 82799991.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19999729) 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, 8913 + ... + 10928.

Almost surely, 2^19999728 is an apocalyptic number.

19999728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

19999728 is an abundant number, since it is smaller than the sum of its proper divisors (43970880).

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

19999728 is a wasteful number, since it uses less digits than its factorization.

19999728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19862 (or 19853 counting only the distinct ones).

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

The square root of 19999728 is about 4472.1055443717. The cubic root of 19999728 is about 271.4405311179.

The spelling of 19999728 in words is "nineteen million, nine hundred ninety-nine thousand, seven hundred twenty-eight".