20919669409 has 4 divisors (see below), whose sum is σ = 20920196016. Its totient is φ = 20919142804.

The previous prime is 20919669383. The next prime is 20919669439. The reversal of 20919669409 is 90496691902.

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 20919669409 - 2¹⁷ = 20919538337 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20919669409.

It is not an unprimeable number, because it can be changed into a prime (20919669439) 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, 198379 + ... + 284944.

It is an arithmetic number, because the mean of its divisors is an integer number (5230049004).

Almost surely, 2^20919669409 is an apocalyptic number.

It is an amenable number.

20919669409 is a deficient number, since it is larger than the sum of its proper divisors (526607).

20919669409 is an equidigital number, since it uses as much as digits as its factorization.

20919669409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 526606.

The product of its (nonzero) digits is 1889568, while the sum is 55.

The spelling of 20919669409 in words is "twenty billion, nine hundred nineteen million, six hundred sixty-nine thousand, four hundred nine".