20549779989 has 4 divisors (see below), whose sum is σ = 27399706656. Its totient is φ = 13699853324.

The previous prime is 20549779969. The next prime is 20549780039. The reversal of 20549779989 is 98997794502.

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 20549779989 - 2¹⁶ = 20549714453 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20549779949) 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, 3424963329 + ... + 3424963334.

It is an arithmetic number, because the mean of its divisors is an integer number (6849926664).

Almost surely, 2^20549779989 is an apocalyptic number.

It is an amenable number.

20549779989 is a deficient number, since it is larger than the sum of its proper divisors (6849926667).

20549779989 is an equidigital number, since it uses as much as digits as its factorization.

20549779989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6849926666.

The product of its (nonzero) digits is 102876480, while the sum is 69.

The spelling of 20549779989 in words is "twenty billion, five hundred forty-nine million, seven hundred seventy-nine thousand, nine hundred eighty-nine".