81301998919681 has 16 divisors (see below), whose sum is σ = 87514616527488. Its totient is φ = 75350582841600.

The previous prime is 81301998919627. The next prime is 81301998919787. The reversal of 81301998919681 is 18691989910318.

It is a happy number.

It is not a de Polignac number, because 81301998919681 - 2¹³ = 81301998911489 is a prime.

It is a super-2 number, since 2×81301998919681² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81301998916681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 432358840 + ... + 432546841.

It is an arithmetic number, because the mean of its divisors is an integer number (5469663532968).

Almost surely, 2^{81301998919681} is an apocalyptic number.

It is an amenable number.

81301998919681 is a deficient number, since it is larger than the sum of its proper divisors (6212617607807).

81301998919681 is a wasteful number, since it uses less digits than its factorization.

81301998919681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 864905832.

The product of its (nonzero) digits is 60466176, while the sum is 73.

It can be divided in two parts, 8130199 and 8919681, that added together give a triangular number (17049880 = T₅₈₃₉).

The spelling of 81301998919681 in words is "eighty-one trillion, three hundred one billion, nine hundred ninety-eight million, nine hundred nineteen thousand, six hundred eighty-one".