20718665417 has 4 divisors (see below), whose sum is σ = 20725463700. Its totient is φ = 20711867136.

The previous prime is 20718665413. The next prime is 20718665437. The reversal of 20718665417 is 71456681702.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2821309456 + 17897355961 = 53116^2 + 133781^2 .

It is a cyclic number.

It is not a de Polignac number, because 20718665417 - 2² = 20718665413 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20718665411) 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, 3394568 + ... + 3400665.

It is an arithmetic number, because the mean of its divisors is an integer number (5181365925).

Almost surely, 2^20718665417 is an apocalyptic number.

It is an amenable number.

20718665417 is a deficient number, since it is larger than the sum of its proper divisors (6798283).

20718665417 is an equidigital number, since it uses as much as digits as its factorization.

20718665417 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6798282.

The product of its (nonzero) digits is 564480, while the sum is 47.

The spelling of 20718665417 in words is "twenty billion, seven hundred eighteen million, six hundred sixty-five thousand, four hundred seventeen".