19780128 has 72 divisors (see below), whose sum is σ = 56717388. Its totient is φ = 6538752.

The previous prime is 19780109. The next prime is 19780141. The reversal of 19780128 is 82108791.

It can be written as a sum of positive squares in 2 ways, for example, as 17740944 + 2039184 = 4212^2 + 1428^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 19780092 and 19780101.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 49626 + ... + 50022.

Almost surely, 2^19780128 is an apocalyptic number.

19780128 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 19780128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28358694).

19780128 is an abundant number, since it is smaller than the sum of its proper divisors (36937260).

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

19780128 is a wasteful number, since it uses less digits than its factorization.

19780128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 586 (or 575 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 19780128 is about 4447.4855817642. The cubic root of 19780128 is about 270.4433867101.

The spelling of 19780128 in words is "nineteen million, seven hundred eighty thousand, one hundred twenty-eight".