81779258880 has 1920 divisors, whose sum is σ = 366771525120. Its totient is φ = 17199267840.

The previous prime is 81779258849. The next prime is 81779258969. The reversal of 81779258880 is 8885297718.

It is a tau number, because it is divible by the number of its divisors (1920).

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, 2210250222 + ... + 2210250258.

It is an arithmetic number, because the mean of its divisors is an integer number (191026836).

Almost surely, 2^81779258880 is an apocalyptic number.

81779258880 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 81779258880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (183385762560).

81779258880 is an abundant number, since it is smaller than the sum of its proper divisors (284992266240).

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

81779258880 is a wasteful number, since it uses less digits than its factorization.

81779258880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122 (or 94 counting only the distinct ones).

The product of its (nonzero) digits is 18063360, while the sum is 63.

The spelling of 81779258880 in words is "eighty-one billion, seven hundred seventy-nine million, two hundred fifty-eight thousand, eight hundred eighty".