71642311661 has 2 divisors, whose sum is σ = 71642311662. Its totient is φ = 71642311660.

The previous prime is 71642311651. The next prime is 71642311673. The reversal of 71642311661 is 16611324617.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 69976120900 + 1666190761 = 264530^2 + 40819^2 .

It is a cyclic number.

It is not a de Polignac number, because 71642311661 - 2³⁰ = 70568569837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71642311621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35821155830 + 35821155831.

It is an arithmetic number, because the mean of its divisors is an integer number (35821155831).

Almost surely, 2^71642311661 is an apocalyptic number.

It is an amenable number.

71642311661 is a deficient number, since it is larger than the sum of its proper divisors (1).

71642311661 is an equidigital number, since it uses as much as digits as its factorization.

71642311661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 38.

The spelling of 71642311661 in words is "seventy-one billion, six hundred forty-two million, three hundred eleven thousand, six hundred sixty-one".