19988640 has 192 divisors, whose sum is σ = 80075520. Its totient is φ = 4561920.

The previous prime is 19988629. The next prime is 19988653. The reversal of 19988640 is 4688991.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 29910 + ... + 30570.

It is an arithmetic number, because the mean of its divisors is an integer number (417060).

Almost surely, 2^19988640 is an apocalyptic number.

19988640 is a gapful number since it is divisible by the number (10) 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 19988640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40037760).

19988640 is an abundant number, since it is smaller than the sum of its proper divisors (60086880).

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

19988640 is a wasteful number, since it uses less digits than its factorization.

19988640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 692 (or 678 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The square root of 19988640 is about 4470.8656879848. The cubic root of 19988640 is about 271.3903589525.

The spelling of 19988640 in words is "nineteen million, nine hundred eighty-eight thousand, six hundred forty".