81771206469888 has 864 divisors, whose sum is σ = 245910531484800. Its totient is φ = 23971759128576.

The previous prime is 81771206469871. The next prime is 81771206469913. The reversal of 81771206469888 is 88896460217718.

It is a super-2 number, since 2×81771206469888² (a number of 29 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 210208756798 + ... + 210208757186.

It is an arithmetic number, because the mean of its divisors is an integer number (284618670700).

Almost surely, 2^{81771206469888} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81771206469888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122955265742400).

81771206469888 is an abundant number, since it is smaller than the sum of its proper divisors (164139325014912).

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

81771206469888 is a wasteful number, since it uses less digits than its factorization.

81771206469888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 759 (or 702 counting only the distinct ones).

The product of its (nonzero) digits is 520224768, while the sum is 75.

The spelling of 81771206469888 in words is "eighty-one trillion, seven hundred seventy-one billion, two hundred six million, four hundred sixty-nine thousand, eight hundred eighty-eight".