20866693656769 has 4 divisors (see below), whose sum is σ = 21178136845744. Its totient is φ = 20555250467796.

The previous prime is 20866693656751. The next prime is 20866693656817. The reversal of 20866693656769 is 96765639666802.

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 20866693656769 - 2²¹ = 20866691559617 is a prime.

It is a super-2 number, since 2×20866693656769² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20866693656569) 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, 155721594387 + ... + 155721594520.

It is an arithmetic number, because the mean of its divisors is an integer number (5294534211436).

Almost surely, 2^{20866693656769} is an apocalyptic number.

It is an amenable number.

20866693656769 is a deficient number, since it is larger than the sum of its proper divisors (311443188975).

20866693656769 is an equidigital number, since it uses as much as digits as its factorization.

20866693656769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311443188974.

The product of its (nonzero) digits is 6348948480, while the sum is 79.

The spelling of 20866693656769 in words is "twenty trillion, eight hundred sixty-six billion, six hundred ninety-three million, six hundred fifty-six thousand, seven hundred sixty-nine".