19857439980 has 576 divisors, whose sum is σ = 77648363520. Its totient is φ = 4157049600.

The previous prime is 19857439939. The next prime is 19857439991. The reversal of 19857439980 is 8993475891.

19857439980 is a `hidden beast` number, since 198 + 5 + 7 + 439 + 9 + 8 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 20037285 + ... + 20038275.

Almost surely, 2^19857439980 is an apocalyptic number.

19857439980 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 19857439980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38824181760).

19857439980 is an abundant number, since it is smaller than the sum of its proper divisors (57790923540).

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

19857439980 is a wasteful number, since it uses less digits than its factorization.

19857439980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1072 (or 1058 counting only the distinct ones).

The product of its (nonzero) digits is 19595520, while the sum is 63.

The spelling of 19857439980 in words is "nineteen billion, eight hundred fifty-seven million, four hundred thirty-nine thousand, nine hundred eighty".