20219808779 has 2 divisors, whose sum is σ = 20219808780. Its totient is φ = 20219808778.

The previous prime is 20219808727. The next prime is 20219808799. The reversal of 20219808779 is 97780891202.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20219808779 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20219808779.

It is not a weakly prime, because it can be changed into another prime (20219808709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10109904389 + 10109904390.

It is an arithmetic number, because the mean of its divisors is an integer number (10109904390).

Almost surely, 2^20219808779 is an apocalyptic number.

20219808779 is a deficient number, since it is larger than the sum of its proper divisors (1).

20219808779 is an equidigital number, since it uses as much as digits as its factorization.

20219808779 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1016064, while the sum is 53.

The spelling of 20219808779 in words is "twenty billion, two hundred nineteen million, eight hundred eight thousand, seven hundred seventy-nine".