71309081 has 2 divisors, whose sum is σ = 71309082. Its totient is φ = 71309080.

The previous prime is 71309053. The next prime is 71309123. The reversal of 71309081 is 18090317.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40960000 + 30349081 = 6400^2 + 5509^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71309081 is a prime.

It is a super-2 number, since 2×71309081² = 10169970066129122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (71309881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35654540 + 35654541.

It is an arithmetic number, because the mean of its divisors is an integer number (35654541).

Almost surely, 2^71309081 is an apocalyptic number.

It is an amenable number.

71309081 is a deficient number, since it is larger than the sum of its proper divisors (1).

71309081 is an equidigital number, since it uses as much as digits as its factorization.

71309081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1512, while the sum is 29.

The square root of 71309081 is about 8444.4704392875. The cubic root of 71309081 is about 414.6817727834.

Adding to 71309081 its reverse (18090317), we get a palindrome (89399398).

The spelling of 71309081 in words is "seventy-one million, three hundred nine thousand, eighty-one".