71020565721 has 32 divisors (see below), whose sum is σ = 124125388800. Its totient is φ = 39274042320.

The previous prime is 71020565719. The next prime is 71020565743. The reversal of 71020565721 is 12756502017.

71020565721 is a `hidden beast` number, since 7 + 1 + 0 + 20 + 565 + 72 + 1 = 666.

It is not a de Polignac number, because 71020565721 - 2¹ = 71020565719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (71020565701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6054951 + ... + 6066668.

It is an arithmetic number, because the mean of its divisors is an integer number (3878918400).

Almost surely, 2^71020565721 is an apocalyptic number.

It is an amenable number.

71020565721 is a deficient number, since it is larger than the sum of its proper divisors (53104823079).

71020565721 is a wasteful number, since it uses less digits than its factorization.

71020565721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12121666 (or 12121660 counting only the distinct ones).

The product of its (nonzero) digits is 29400, while the sum is 36.

The spelling of 71020565721 in words is "seventy-one billion, twenty million, five hundred sixty-five thousand, seven hundred twenty-one".