1981463378976 has 72 divisors (see below), whose sum is σ = 5663982427740. Its totient is φ = 657065558016.

The previous prime is 1981463378963. The next prime is 1981463378981. The reversal of 1981463378976 is 6798733641891.

It is a happy number.

1981463378976 is a `hidden beast` number, since 1 + 9 + 8 + 1 + 463 + 3 + 78 + 97 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1933423506576 + 48039872400 = 1390476^2 + 219180^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-3 number, since 3×1981463378976³ (a number of 38 digits) contains 333 as substring.

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 an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17768461 + ... + 17879628.

Almost surely, 2^{1981463378976} is an apocalyptic number.

1981463378976 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1981463378976 is an abundant number, since it is smaller than the sum of its proper divisors (3682519048764).

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

1981463378976 is a wasteful number, since it uses less digits than its factorization.

1981463378976 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35648298 (or 35648287 counting only the distinct ones).

The product of its digits is 329204736, while the sum is 72.

The spelling of 1981463378976 in words is "one trillion, nine hundred eighty-one billion, four hundred sixty-three million, three hundred seventy-eight thousand, nine hundred seventy-six".