20219808709 has 2 divisors, whose sum is σ = 20219808710. Its totient is φ = 20219808708.

The previous prime is 20219808703. The next prime is 20219808727. The reversal of 20219808709 is 90780891202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20205201025 + 14607684 = 142145^2 + 3822^2 .

It is a cyclic number.

It is not a de Polignac number, because 20219808709 - 2⁵ = 20219808677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20219808703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10109904354 + 10109904355.

It is an arithmetic number, because the mean of its divisors is an integer number (10109904355).

Almost surely, 2^20219808709 is an apocalyptic number.

It is an amenable number.

20219808709 is a deficient number, since it is larger than the sum of its proper divisors (1).

20219808709 is an equidigital number, since it uses as much as digits as its factorization.

20219808709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145152, while the sum is 46.

The spelling of 20219808709 in words is "twenty billion, two hundred nineteen million, eight hundred eight thousand, seven hundred nine".