20716217447 has 2 divisors, whose sum is σ = 20716217448. Its totient is φ = 20716217446.

The previous prime is 20716217437. The next prime is 20716217491. The reversal of 20716217447 is 74471261702.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20716217447 - 2¹² = 20716213351 is a prime.

It is a super-2 number, since 2×20716217447² (a number of 21 digits) contains 22 as substring.

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, 10358108723 + 10358108724.

It is an arithmetic number, because the mean of its divisors is an integer number (10358108724).

Almost surely, 2^20716217447 is an apocalyptic number.

20716217447 is a deficient number, since it is larger than the sum of its proper divisors (1).

20716217447 is an equidigital number, since it uses as much as digits as its factorization.

20716217447 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 131712, while the sum is 41.

The spelling of 20716217447 in words is "twenty billion, seven hundred sixteen million, two hundred seventeen thousand, four hundred forty-seven".