19860640 has 48 divisors (see below), whose sum is σ = 47423880. Its totient is φ = 7859200.

The previous prime is 19860629. The next prime is 19860647. The reversal of 19860640 is 4606891.

It can be written as a sum of positive squares in 4 ways, for example, as 19324816 + 535824 = 4396^2 + 732^2 .

It is a junction number, because it is equal to n+sod(n) for n = 19860596 and 19860605.

It is not an unprimeable number, because it can be changed into a prime (19860647) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15546 + ... + 16774.

Almost surely, 2^19860640 is an apocalyptic number.

19860640 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 19860640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23711940).

19860640 is an abundant number, since it is smaller than the sum of its proper divisors (27563240).

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

19860640 is a wasteful number, since it uses less digits than its factorization.

19860640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1345 (or 1337 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 19860640 is about 4456.5277963904. The cubic root of 19860640 is about 270.8098228638.

The spelling of 19860640 in words is "nineteen million, eight hundred sixty thousand, six hundred forty".