20445779761 has 4 divisors (see below), whose sum is σ = 22304487024. Its totient is φ = 18587072500.

The previous prime is 20445779747. The next prime is 20445779801. The reversal of 20445779761 is 16797754402.

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 a de Polignac number, because none of the positive numbers 2^k-20445779761 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20445779699 and 20445779708.

It is not an unprimeable number, because it can be changed into a prime (20445779741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 929353615 + ... + 929353636.

It is an arithmetic number, because the mean of its divisors is an integer number (5576121756).

Almost surely, 2^20445779761 is an apocalyptic number.

It is an amenable number.

20445779761 is a deficient number, since it is larger than the sum of its proper divisors (1858707263).

20445779761 is a wasteful number, since it uses less digits than its factorization.

20445779761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1858707262.

The product of its (nonzero) digits is 2963520, while the sum is 52.

The spelling of 20445779761 in words is "twenty billion, four hundred forty-five million, seven hundred seventy-nine thousand, seven hundred sixty-one".