81773987472 has 240 divisors, whose sum is σ = 237849955200. Its totient is φ = 26212792320.

The previous prime is 81773987461. The next prime is 81773987479. The reversal of 81773987472 is 27478937718.

81773987472 is a `hidden beast` number, since 8 + 1 + 7 + 73 + 98 + 7 + 472 = 666.

It is a Smith number, since the sum of its digits (63) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (81773987479) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 88981029 + ... + 88981947.

It is an arithmetic number, because the mean of its divisors is an integer number (991041480).

Almost surely, 2^81773987472 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 81773987472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118924977600).

81773987472 is an abundant number, since it is smaller than the sum of its proper divisors (156075967728).

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

81773987472 is a wasteful number, since it uses less digits than its factorization.

81773987472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1206 (or 1197 counting only the distinct ones).

The product of its digits is 33191424, while the sum is 63.

The spelling of 81773987472 in words is "eighty-one billion, seven hundred seventy-three million, nine hundred eighty-seven thousand, four hundred seventy-two".