81977916324240 has 200 divisors, whose sum is σ = 299706788103360. Its totient is φ = 20710210408704.

The previous prime is 81977916324223. The next prime is 81977916324277. The reversal of 81977916324240 is 4242361977918.

81977916324240 is a `hidden beast` number, since 8 + 1 + 97 + 7 + 91 + 6 + 32 + 424 + 0 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 332795644 + ... + 333041883.

Almost surely, 2^{81977916324240} is an apocalyptic number.

81977916324240 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81977916324240 is an abundant number, since it is smaller than the sum of its proper divisors (217728871779120).

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

81977916324240 is a wasteful number, since it uses less digits than its factorization.

81977916324240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 665837571 (or 665837556 counting only the distinct ones).

The product of its (nonzero) digits is 36578304, while the sum is 63.

The spelling of 81977916324240 in words is "eighty-one trillion, nine hundred seventy-seven billion, nine hundred sixteen million, three hundred twenty-four thousand, two hundred forty".