20716217437 has 2 divisors, whose sum is σ = 20716217438. Its totient is φ = 20716217436.

The previous prime is 20716217407. The next prime is 20716217447. The reversal of 20716217437 is 73471261702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13100862681 + 7615354756 = 114459^2 + 87266^2 .

It is a cyclic number.

It is not a de Polignac number, because 20716217437 - 2¹⁹ = 20715693149 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20716217437.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20716217407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10358108718 + 10358108719.

It is an arithmetic number, because the mean of its divisors is an integer number (10358108719).

Almost surely, 2^20716217437 is an apocalyptic number.

It is an amenable number.

20716217437 is a deficient number, since it is larger than the sum of its proper divisors (1).

20716217437 is an equidigital number, since it uses as much as digits as its factorization.

20716217437 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 98784, while the sum is 40.

The spelling of 20716217437 in words is "twenty billion, seven hundred sixteen million, two hundred seventeen thousand, four hundred thirty-seven".