1981904511456 has 288 divisors, whose sum is σ = 5822251475040. Its totient is φ = 639123996672.

The previous prime is 1981904511449. The next prime is 1981904511469. The reversal of 1981904511456 is 6541154091891.

1981904511456 is a `hidden beast` number, since 1 + 9 + 81 + 9 + 0 + 4 + 511 + 45 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 965368926 + ... + 965370978.

It is an arithmetic number, because the mean of its divisors is an integer number (20216150955).

Almost surely, 2^{1981904511456} is an apocalyptic number.

1981904511456 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 1981904511456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2911125737520).

1981904511456 is an abundant number, since it is smaller than the sum of its proper divisors (3840346963584).

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

1981904511456 is a wasteful number, since it uses less digits than its factorization.

1981904511456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2818 (or 2807 counting only the distinct ones).

The product of its (nonzero) digits is 1555200, while the sum is 54.

The spelling of 1981904511456 in words is "one trillion, nine hundred eighty-one billion, nine hundred four million, five hundred eleven thousand, four hundred fifty-six".