19880640 has 280 divisors, whose sum is σ = 77449680. Its totient is φ = 4810752.

The previous prime is 19880629. The next prime is 19880647. The reversal of 19880640 is 4608891.

It is a happy number.

19880640 is a `hidden beast` number, since 1 + 9 + 8 + 8 + 0 + 640 = 666.

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 = 19880595 and 19880604.

It is not an unprimeable number, because it can be changed into a prime (19880647) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 336931 + ... + 336989.

It is an arithmetic number, because the mean of its divisors is an integer number (276606).

Almost surely, 2^19880640 is an apocalyptic number.

19880640 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 19880640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38724840).

19880640 is an abundant number, since it is smaller than the sum of its proper divisors (57569040).

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

19880640 is a wasteful number, since it uses less digits than its factorization.

19880640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101 (or 82 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 19880640 is about 4458.7711311526. The cubic root of 19880640 is about 270.9006957227.

The spelling of 19880640 in words is "nineteen million, eight hundred eighty thousand, six hundred forty".