71009721 has 12 divisors (see below), whose sum is σ = 102665940. Its totient is φ = 47295360.

The previous prime is 71009699. The next prime is 71009759. The reversal of 71009721 is 12790017.

It can be written as a sum of positive squares in 2 ways, for example, as 31809600 + 39200121 = 5640^2 + 6261^2 .

It is not a de Polignac number, because 71009721 - 2⁵ = 71009689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (71009791) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8541 + ... + 14661.

It is an arithmetic number, because the mean of its divisors is an integer number (8555495).

Almost surely, 2^71009721 is an apocalyptic number.

It is an amenable number.

71009721 is a deficient number, since it is larger than the sum of its proper divisors (31656219).

71009721 is a wasteful number, since it uses less digits than its factorization.

71009721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7416 (or 7413 counting only the distinct ones).

The product of its (nonzero) digits is 882, while the sum is 27.

The square root of 71009721 is about 8426.7265886583. The cubic root of 71009721 is about 414.1006721500.

Adding to 71009721 its reverse (12790017), we get a palindrome (83799738).

The spelling of 71009721 in words is "seventy-one million, nine thousand, seven hundred twenty-one".