81301998919680 has 2688 divisors, whose sum is σ = 373091773317120. Its totient is φ = 15865369067520.

The previous prime is 81301998919627. The next prime is 81301998919787. The reversal of 81301998919680 is 8691989910318.

81301998919680 is a `hidden beast` number, since 81 + 301 + 9 + 9 + 89 + 1 + 96 + 80 = 666.

It is a tau number, because it is divible by the number of its divisors (2688).

It is a super-2 number, since 2×81301998919680² (a number of 29 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 81301998919599 and 81301998919608.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 68493680047 + ... + 68493681233.

Almost surely, 2^{81301998919680} is an apocalyptic number.

81301998919680 is a gapful number since it is divisible by the number (80) 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 81301998919680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (186545886658560).

81301998919680 is an abundant number, since it is smaller than the sum of its proper divisors (291789774397440).

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

81301998919680 is a wasteful number, since it uses less digits than its factorization.

81301998919680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1388 (or 1361 counting only the distinct ones).

The product of its (nonzero) digits is 60466176, while the sum is 72.

The spelling of 81301998919680 in words is "eighty-one trillion, three hundred one billion, nine hundred ninety-eight million, nine hundred nineteen thousand, six hundred eighty".