71221081 has 2 divisors, whose sum is σ = 71221082. Its totient is φ = 71221080.

The previous prime is 71221049. The next prime is 71221091. The reversal of 71221081 is 18012217.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69305625 + 1915456 = 8325^2 + 1384^2 .

It is an emirp because it is prime and its reverse (18012217) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71221081 - 2⁵ = 71221049 is a prime.

It is a super-2 number, since 2×71221081² = 10144884757617122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (71221001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35610540 + 35610541.

It is an arithmetic number, because the mean of its divisors is an integer number (35610541).

Almost surely, 2^71221081 is an apocalyptic number.

It is an amenable number.

71221081 is a deficient number, since it is larger than the sum of its proper divisors (1).

71221081 is an equidigital number, since it uses as much as digits as its factorization.

71221081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 224, while the sum is 22.

The square root of 71221081 is about 8439.2583204924. The cubic root of 71221081 is about 414.5111212247.

Adding to 71221081 its reverse (18012217), we get a palindrome (89233298).

The spelling of 71221081 in words is "seventy-one million, two hundred twenty-one thousand, eighty-one".