20716217449 has 4 divisors (see below), whose sum is σ = 21384482560. Its totient is φ = 20047952340.

The previous prime is 20716217447. The next prime is 20716217491. The reversal of 20716217449 is 94471261702.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 94471261702 = 2 ⋅47235630851.

It is not a de Polignac number, because 20716217449 - 2¹ = 20716217447 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20716217447) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 334132509 + ... + 334132570.

It is an arithmetic number, because the mean of its divisors is an integer number (5346120640).

Almost surely, 2^20716217449 is an apocalyptic number.

It is an amenable number.

20716217449 is a deficient number, since it is larger than the sum of its proper divisors (668265111).

20716217449 is an equidigital number, since it uses as much as digits as its factorization.

20716217449 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 668265110.

The product of its (nonzero) digits is 169344, while the sum is 43.

The spelling of 20716217449 in words is "twenty billion, seven hundred sixteen million, two hundred seventeen thousand, four hundred forty-nine".