71137721 has 2 divisors, whose sum is σ = 71137722. Its totient is φ = 71137720.

The previous prime is 71137711. The next prime is 71137739. The reversal of 71137721 is 12773117.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64320400 + 6817321 = 8020^2 + 2611^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71137721 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (71137711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35568860 + 35568861.

It is an arithmetic number, because the mean of its divisors is an integer number (35568861).

Almost surely, 2^71137721 is an apocalyptic number.

It is an amenable number.

71137721 is a deficient number, since it is larger than the sum of its proper divisors (1).

71137721 is an equidigital number, since it uses as much as digits as its factorization.

71137721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2058, while the sum is 29.

The square root of 71137721 is about 8434.3180518641. The cubic root of 71137721 is about 414.3493379608.

The spelling of 71137721 in words is "seventy-one million, one hundred thirty-seven thousand, seven hundred twenty-one".