19857426488640 has 784 divisors, whose sum is σ = 76413503262096. Its totient is φ = 4883875430400.

The previous prime is 19857426488609. The next prime is 19857426488719. The reversal of 19857426488640 is 4688462475891.

19857426488640 is a `hidden beast` number, since 1 + 9 + 8 + 574 + 2 + 6 + 4 + 8 + 8 + 6 + 40 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 7641730439424 + 12215696049216 = 2764368^2 + 3495096^2 .

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 5279824360 + ... + 5279828120.

Almost surely, 2^{19857426488640} is an apocalyptic number.

19857426488640 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 19857426488640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38206751631048).

19857426488640 is an abundant number, since it is smaller than the sum of its proper divisors (56556076773456).

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

19857426488640 is a wasteful number, since it uses less digits than its factorization.

19857426488640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5550 (or 5525 counting only the distinct ones).

The product of its (nonzero) digits is 743178240, while the sum is 72.

The spelling of 19857426488640 in words is "nineteen trillion, eight hundred fifty-seven billion, four hundred twenty-six million, four hundred eighty-eight thousand, six hundred forty".