19661573543040 has 4608 divisors, whose sum is σ = 91257178521600. Its totient is φ = 3982705459200.

The previous prime is 19661573543011. The next prime is 19661573543041. The reversal of 19661573543040 is 4034537516691.

19661573543040 is a `hidden beast` number, since 1 + 9 + 6 + 6 + 1 + 57 + 3 + 543 + 0 + 40 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (19661573543041) by changing a digit.

It is a polite number, since it can be written in 575 ways as a sum of consecutive naturals, for example, 248880677721 + ... + 248880677799.

It is an arithmetic number, because the mean of its divisors is an integer number (19804075200).

Almost surely, 2^{19661573543040} is an apocalyptic number.

19661573543040 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 19661573543040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45628589260800).

19661573543040 is an abundant number, since it is smaller than the sum of its proper divisors (71595604978560).

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

19661573543040 is a wasteful number, since it uses less digits than its factorization.

19661573543040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206 (or 163 counting only the distinct ones).

The product of its (nonzero) digits is 8164800, while the sum is 54.

The spelling of 19661573543040 in words is "nineteen trillion, six hundred sixty-one billion, five hundred seventy-three million, five hundred forty-three thousand, forty".