20665213297 has 4 divisors (see below), whose sum is σ = 20666228976. Its totient is φ = 20664197620.

The previous prime is 20665213279. The next prime is 20665213337. The reversal of 20665213297 is 79231256602.

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.

It is a cyclic number.

It is not a de Polignac number, because 20665213297 - 2¹¹ = 20665211249 is a prime.

It is a super-2 number, since 2×20665213297² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20665213237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 476683 + ... + 518224.

It is an arithmetic number, because the mean of its divisors is an integer number (5166557244).

Almost surely, 2^20665213297 is an apocalyptic number.

It is an amenable number.

20665213297 is a deficient number, since it is larger than the sum of its proper divisors (1015679).

20665213297 is an equidigital number, since it uses as much as digits as its factorization.

20665213297 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1015678.

The product of its (nonzero) digits is 272160, while the sum is 43.

Adding to 20665213297 its reverse (79231256602), we get a palindrome (99896469899).

The spelling of 20665213297 in words is "twenty billion, six hundred sixty-five million, two hundred thirteen thousand, two hundred ninety-seven".