1981597149936 has 240 divisors, whose sum is σ = 5821770240000. Its totient is φ = 628467420672.

The previous prime is 1981597149877. The next prime is 1981597149937. The reversal of 1981597149936 is 6399417951891.

1981597149936 is a `hidden beast` number, since 1 + 9 + 8 + 15 + 97 + 1 + 499 + 36 = 666.

It is a hoax number, since the sum of its digits (72) coincides with the sum of the digits of its distinct 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 not an unprimeable number, because it can be changed into a prime (1981597149937) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 375370945 + ... + 375376223.

It is an arithmetic number, because the mean of its divisors is an integer number (24257376000).

Almost surely, 2^{1981597149936} is an apocalyptic number.

1981597149936 is a gapful number since it is divisible by the number (16) 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 1981597149936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2910885120000).

1981597149936 is an abundant number, since it is smaller than the sum of its proper divisors (3840173090064).

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

1981597149936 is a wasteful number, since it uses less digits than its factorization.

1981597149936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6876 (or 6867 counting only the distinct ones).

The product of its digits is 132269760, while the sum is 72.

The spelling of 1981597149936 in words is "one trillion, nine hundred eighty-one billion, five hundred ninety-seven million, one hundred forty-nine thousand, nine hundred thirty-six".