71243021 has 2 divisors, whose sum is σ = 71243022. Its totient is φ = 71243020.

The previous prime is 71242999. The next prime is 71243071. The reversal of 71243021 is 12034217.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65772100 + 5470921 = 8110^2 + 2339^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71243021 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 71242984 and 71243002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71243071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35621510 + 35621511.

It is an arithmetic number, because the mean of its divisors is an integer number (35621511).

Almost surely, 2^71243021 is an apocalyptic number.

It is an amenable number.

71243021 is a deficient number, since it is larger than the sum of its proper divisors (1).

71243021 is an equidigital number, since it uses as much as digits as its factorization.

71243021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 71243021 is about 8440.5580976616. The cubic root of 71243021 is about 414.5536809097.

Adding to 71243021 its reverse (12034217), we get a palindrome (83277238).

The spelling of 71243021 in words is "seventy-one million, two hundred forty-three thousand, twenty-one".