19985040 has 120 divisors (see below), whose sum is σ = 68854968. Its totient is φ = 5191680.

The previous prime is 19985033. The next prime is 19985051. The reversal of 19985040 is 4058991.

It can be written as a sum of positive squares in 4 ways, for example, as 2944656 + 17040384 = 1716^2 + 4128^2 .

It is a tau number, because it is divible by the number of its divisors (120).

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 = 19984986 and 19985004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 29182 + ... + 29858.

Almost surely, 2^19985040 is an apocalyptic number.

19985040 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 19985040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34427484).

19985040 is an abundant number, since it is smaller than the sum of its proper divisors (48869928).

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

19985040 is a wasteful number, since it uses less digits than its factorization.

19985040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 737 (or 728 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 19985040 is about 4470.4630632631. The cubic root of 19985040 is about 271.3740652985.

The spelling of 19985040 in words is "nineteen million, nine hundred eighty-five thousand, forty".