1981193195520 has 3328 divisors, whose sum is σ = 9662496768000. Its totient is φ = 372650803200.

The previous prime is 1981193195491. The next prime is 1981193195549. The reversal of 1981193195520 is 255913911891.

1981193195520 is a `hidden beast` number, since 1 + 9 + 8 + 11 + 93 + 19 + 5 + 520 = 666.

It is an interprime number because it is at equal distance from previous prime (1981193195491) and next prime (1981193195549).

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

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 25078394841 + ... + 25078394919.

Almost surely, 2^{1981193195520} is an apocalyptic number.

1981193195520 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 1981193195520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4831248384000).

1981193195520 is an abundant number, since it is smaller than the sum of its proper divisors (7681303572480).

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

1981193195520 is a wasteful number, since it uses less digits than its factorization.

1981193195520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185 (or 157 counting only the distinct ones).

The product of its (nonzero) digits is 874800, while the sum is 54.

The spelling of 1981193195520 in words is "one trillion, nine hundred eighty-one billion, one hundred ninety-three million, one hundred ninety-five thousand, five hundred twenty".