19897128 has 48 divisors (see below), whose sum is σ = 54431520. Its totient is φ = 6565536.

The previous prime is 19897127. The next prime is 19897159. The reversal of 19897128 is 82179891.

It is not an unprimeable number, because it can be changed into a prime (19897127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6075 + ... + 8757.

It is an arithmetic number, because the mean of its divisors is an integer number (1133990).

Almost surely, 2^19897128 is an apocalyptic number.

19897128 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 19897128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27215760).

19897128 is an abundant number, since it is smaller than the sum of its proper divisors (34534392).

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

19897128 is a wasteful number, since it uses less digits than its factorization.

19897128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2798 (or 2791 counting only the distinct ones).

The product of its digits is 72576, while the sum is 45.

The square root of 19897128 is about 4460.6196878909. The cubic root of 19897128 is about 270.9755654862.

The spelling of 19897128 in words is "nineteen million, eight hundred ninety-seven thousand, one hundred twenty-eight".