71311572 has 18 divisors (see below), whose sum is σ = 180259898. Its totient is φ = 23770512.

The previous prime is 71311571. The next prime is 71311577. The reversal of 71311572 is 27511317.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 67174416 + 4137156 = 8196^2 + 2034^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×71311572² = 10170680602222368, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71311571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 990403 + ... + 990474.

Almost surely, 2^71311572 is an apocalyptic number.

It is an amenable number.

71311572 is an abundant number, since it is smaller than the sum of its proper divisors (108948326).

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

71311572 is a wasteful number, since it uses less digits than its factorization.

71311572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1980887 (or 1980882 counting only the distinct ones).

The product of its digits is 1470, while the sum is 27.

The square root of 71311572 is about 8444.6179309664. The cubic root of 71311572 is about 414.6866013422.

Adding to 71311572 its reverse (27511317), we get a palindrome (98822889).

The spelling of 71311572 in words is "seventy-one million, three hundred eleven thousand, five hundred seventy-two".