71680037921 has 2 divisors, whose sum is σ = 71680037922. Its totient is φ = 71680037920.

The previous prime is 71680037917. The next prime is 71680037981. The reversal of 71680037921 is 12973008617.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47834501521 + 23845536400 = 218711^2 + 154420^2 .

It is a cyclic number.

It is not a de Polignac number, because 71680037921 - 2² = 71680037917 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (71680037981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35840018960 + 35840018961.

It is an arithmetic number, because the mean of its divisors is an integer number (35840018961).

Almost surely, 2^71680037921 is an apocalyptic number.

It is an amenable number.

71680037921 is a deficient number, since it is larger than the sum of its proper divisors (1).

71680037921 is an equidigital number, since it uses as much as digits as its factorization.

71680037921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 127008, while the sum is 44.

The spelling of 71680037921 in words is "seventy-one billion, six hundred eighty million, thirty-seven thousand, nine hundred twenty-one".