20969179809 has 4 divisors (see below), whose sum is σ = 27958906416. Its totient is φ = 13979453204.

The previous prime is 20969179709. The next prime is 20969179841. The reversal of 20969179809 is 90897196902.

It is a happy number.

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 20969179809 - 2¹³ = 20969171617 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20969179849) 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, 3494863299 + ... + 3494863304.

It is an arithmetic number, because the mean of its divisors is an integer number (6989726604).

Almost surely, 2^20969179809 is an apocalyptic number.

It is an amenable number.

20969179809 is a deficient number, since it is larger than the sum of its proper divisors (6989726607).

20969179809 is an equidigital number, since it uses as much as digits as its factorization.

20969179809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6989726606.

The product of its (nonzero) digits is 4408992, while the sum is 60.

The spelling of 20969179809 in words is "twenty billion, nine hundred sixty-nine million, one hundred seventy-nine thousand, eight hundred nine".