81771480 has 192 divisors, whose sum is σ = 312287040. Its totient is φ = 18164736.

The previous prime is 81771451. The next prime is 81771491. The reversal of 81771480 is 8417718.

81771480 is a `hidden beast` number, since 8 + 177 + 1 + 480 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 92802 + ... + 93678.

It is an arithmetic number, because the mean of its divisors is an integer number (1626495).

Almost surely, 2^81771480 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 81771480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (156143520).

81771480 is an abundant number, since it is smaller than the sum of its proper divisors (230515560).

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

81771480 is a wasteful number, since it uses less digits than its factorization.

81771480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 938 (or 931 counting only the distinct ones).

The product of its (nonzero) digits is 12544, while the sum is 36.

The square root of 81771480 is about 9042.7584287097. The cubic root of 81771480 is about 434.0441954894.

The spelling of 81771480 in words is "eighty-one million, seven hundred seventy-one thousand, four hundred eighty".