71721313 has 2 divisors, whose sum is σ = 71721314. Its totient is φ = 71721312.

The previous prime is 71721311. The next prime is 71721319. The reversal of 71721313 is 31312717.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40551424 + 31169889 = 6368^2 + 5583^2 .

It is a cyclic number.

It is not a de Polignac number, because 71721313 - 2¹ = 71721311 is a prime.

Together with 71721311, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (71721311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35860656 + 35860657.

It is an arithmetic number, because the mean of its divisors is an integer number (35860657).

Almost surely, 2^71721313 is an apocalyptic number.

It is an amenable number.

71721313 is a deficient number, since it is larger than the sum of its proper divisors (1).

71721313 is an equidigital number, since it uses as much as digits as its factorization.

71721313 is an evil number, because the sum of its binary digits is even.

The product of its digits is 882, while the sum is 25.

The square root of 71721313 is about 8468.8436636887. The cubic root of 71721313 is about 415.4793184418.

The spelling of 71721313 in words is "seventy-one million, seven hundred twenty-one thousand, three hundred thirteen".