71665213 has 2 divisors, whose sum is σ = 71665214. Its totient is φ = 71665212.

The previous prime is 71665201. The next prime is 71665229. The reversal of 71665213 is 31256617.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 71537764 + 127449 = 8458^2 + 357^2 .

It is a cyclic number.

It is not a de Polignac number, because 71665213 - 2¹³ = 71657021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71665313) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35832606 + 35832607.

It is an arithmetic number, because the mean of its divisors is an integer number (35832607).

Almost surely, 2^71665213 is an apocalyptic number.

It is an amenable number.

71665213 is a deficient number, since it is larger than the sum of its proper divisors (1).

71665213 is an equidigital number, since it uses as much as digits as its factorization.

71665213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7560, while the sum is 31.

The square root of 71665213 is about 8465.5308752612. The cubic root of 71665213 is about 415.3709616709.

The spelling of 71665213 in words is "seventy-one million, six hundred sixty-five thousand, two hundred thirteen".