19784581491840 has 256 divisors, whose sum is σ = 69044768461440. Its totient is φ = 4778945740800.

The previous prime is 19784581491817. The next prime is 19784581491841. The reversal of 19784581491840 is 4819418548791.

It is not an unprimeable number, because it can be changed into a prime (19784581491841) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4159320 + ... + 7541160.

Almost surely, 2^{19784581491840} is an apocalyptic number.

19784581491840 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 19784581491840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34522384230720).

19784581491840 is an abundant number, since it is smaller than the sum of its proper divisors (49260186969600).

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

19784581491840 is a wasteful number, since it uses less digits than its factorization.

19784581491840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3382151 (or 3382139 counting only the distinct ones).

The product of its (nonzero) digits is 92897280, while the sum is 69.

The spelling of 19784581491840 in words is "nineteen trillion, seven hundred eighty-four billion, five hundred eighty-one million, four hundred ninety-one thousand, eight hundred forty".