26021780909 has 2 divisors, whose sum is σ = 26021780910. Its totient is φ = 26021780908.

The previous prime is 26021780893. The next prime is 26021780957. The reversal of 26021780909 is 90908712062.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17437202500 + 8584578409 = 132050^2 + 92653^2 .

It is a cyclic number.

It is not a de Polignac number, because 26021780909 - 2⁴ = 26021780893 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 26021780909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (26021780009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13010890454 + 13010890455.

It is an arithmetic number, because the mean of its divisors is an integer number (13010890455).

Almost surely, 2^26021780909 is an apocalyptic number.

It is an amenable number.

26021780909 is a deficient number, since it is larger than the sum of its proper divisors (1).

26021780909 is an equidigital number, since it uses as much as digits as its factorization.

26021780909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108864, while the sum is 44.

The spelling of 26021780909 in words is "twenty-six billion, twenty-one million, seven hundred eighty thousand, nine hundred nine".