19997583851520 has 960 divisors, whose sum is σ = 78028785838080. Its totient is φ = 4818862080000.

The previous prime is 19997583851459. The next prime is 19997583851533. The reversal of 19997583851520 is 2515838579991.

19997583851520 is a `hidden beast` number, since 1 + 9 + 9 + 9 + 7 + 5 + 83 + 8 + 515 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (960).

It is a Smith number, since the sum of its digits (72) coincides with the sum of the digits of its prime factors.

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 63 ways as a sum of consecutive naturals, for example, 4209129145 + ... + 4209133895.

It is an arithmetic number, because the mean of its divisors is an integer number (81279985248).

Almost surely, 2^{19997583851520} is an apocalyptic number.

19997583851520 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 19997583851520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39014392919040).

19997583851520 is an abundant number, since it is smaller than the sum of its proper divisors (58031201986560).

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

19997583851520 is a wasteful number, since it uses less digits than its factorization.

19997583851520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4977 (or 4945 counting only the distinct ones).

The product of its (nonzero) digits is 244944000, while the sum is 72.

The spelling of 19997583851520 in words is "nineteen trillion, nine hundred ninety-seven billion, five hundred eighty-three million, eight hundred fifty-one thousand, five hundred twenty".