81413777680 has 80 divisors (see below), whose sum is σ = 190253448000. Its totient is φ = 32399552000.

The previous prime is 81413777671. The next prime is 81413777693. The reversal of 81413777680 is 8677731418.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×81413777680² (a number of 23 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (52) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24676671 + ... + 24679969.

It is an arithmetic number, because the mean of its divisors is an integer number (2378168100).

Almost surely, 2^81413777680 is an apocalyptic number.

81413777680 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81413777680 is an abundant number, since it is smaller than the sum of its proper divisors (108839670320).

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

81413777680 is a wasteful number, since it uses less digits than its factorization.

81413777680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4792 (or 4786 counting only the distinct ones).

The product of its (nonzero) digits is 1580544, while the sum is 52.

The spelling of 81413777680 in words is "eighty-one billion, four hundred thirteen million, seven hundred seventy-seven thousand, six hundred eighty".