20665298971 has 4 divisors (see below), whose sum is σ = 20665839744. Its totient is φ = 20664758200.

The previous prime is 20665298939. The next prime is 20665298999. The reversal of 20665298971 is 17989256602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17989256602 = 2 ⋅8994628301.

It is a cyclic number.

It is not a de Polignac number, because 20665298971 - 2⁵ = 20665298939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20665292971) 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, 208315 + ... + 291076.

It is an arithmetic number, because the mean of its divisors is an integer number (5166459936).

Almost surely, 2^20665298971 is an apocalyptic number.

20665298971 is a deficient number, since it is larger than the sum of its proper divisors (540773).

20665298971 is an equidigital number, since it uses as much as digits as its factorization.

20665298971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 540772.

The product of its (nonzero) digits is 3265920, while the sum is 55.

The spelling of 20665298971 in words is "twenty billion, six hundred sixty-five million, two hundred ninety-eight thousand, nine hundred seventy-one".