71781072 has 120 divisors (see below), whose sum is σ = 216111168. Its totient is φ = 20444160.

The previous prime is 71781049. The next prime is 71781077. The reversal of 71781072 is 27018717.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71781077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 98373 + ... + 99099.

Almost surely, 2^71781072 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 71781072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108055584).

71781072 is an abundant number, since it is smaller than the sum of its proper divisors (144330096).

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

71781072 is a wasteful number, since it uses less digits than its factorization.

71781072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 777 (or 760 counting only the distinct ones).

The product of its (nonzero) digits is 5488, while the sum is 33.

The square root of 71781072 is about 8472.3710966883. The cubic root of 71781072 is about 415.5946804121.

Adding to 71781072 its reverse (27018717), we get a palindrome (98799789).

The spelling of 71781072 in words is "seventy-one million, seven hundred eighty-one thousand, seventy-two".