19861438680 has 256 divisors, whose sum is σ = 68257728000. Its totient is φ = 5133279744.

The previous prime is 19861438679. The next prime is 19861438693. The reversal of 19861438680 is 8683416891.

19861438680 is a `hidden beast` number, since 1 + 98 + 61 + 438 + 68 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12266911 + ... + 12268529.

It is an arithmetic number, because the mean of its divisors is an integer number (266631750).

Almost surely, 2^19861438680 is an apocalyptic number.

19861438680 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 19861438680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34128864000).

19861438680 is an abundant number, since it is smaller than the sum of its proper divisors (48396289320).

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

19861438680 is a wasteful number, since it uses less digits than its factorization.

19861438680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1983 (or 1973 counting only the distinct ones).

The product of its (nonzero) digits is 1990656, while the sum is 54.

The spelling of 19861438680 in words is "nineteen billion, eight hundred sixty-one million, four hundred thirty-eight thousand, six hundred eighty".