71331021 has 24 divisors (see below), whose sum is σ = 107310840. Its totient is φ = 45619200.

The previous prime is 71331011. The next prime is 71331037. The reversal of 71331021 is 12013317.

It can be written as a sum of positive squares in 4 ways, for example, as 12996 + 71318025 = 114^2 + 8445^2 .

It is not a de Polignac number, because 71331021 - 2⁶ = 71330957 is a prime.

It is a super-2 number, since 2×71331021² = 10176229113804882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 71330985 and 71331003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71331011) 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, 20925 + ... + 24093.

It is an arithmetic number, because the mean of its divisors is an integer number (4471285).

Almost surely, 2^71331021 is an apocalyptic number.

It is an amenable number.

71331021 is a deficient number, since it is larger than the sum of its proper divisors (35979819).

71331021 is a wasteful number, since it uses less digits than its factorization.

71331021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3277 (or 3274 counting only the distinct ones).

The product of its (nonzero) digits is 126, while the sum is 18.

The square root of 71331021 is about 8445.7694143281. The cubic root of 71331021 is about 414.7242974523.

Adding to 71331021 its reverse (12013317), we get a palindrome (83344338).

The spelling of 71331021 in words is "seventy-one million, three hundred thirty-one thousand, twenty-one".