26655556721 has 2 divisors, whose sum is σ = 26655556722. Its totient is φ = 26655556720.

The previous prime is 26655556651. The next prime is 26655556747. The reversal of 26655556721 is 12765555662.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20948509696 + 5707047025 = 144736^2 + 75545^2 .

It is a cyclic number.

It is not a de Polignac number, because 26655556721 - 2¹⁸ = 26655294577 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 26655556721.

It is not a weakly prime, because it can be changed into another prime (26655556321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13327778360 + 13327778361.

It is an arithmetic number, because the mean of its divisors is an integer number (13327778361).

Almost surely, 2^26655556721 is an apocalyptic number.

It is an amenable number.

26655556721 is a deficient number, since it is larger than the sum of its proper divisors (1).

26655556721 is an equidigital number, since it uses as much as digits as its factorization.

26655556721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3780000, while the sum is 50.

The spelling of 26655556721 in words is "twenty-six billion, six hundred fifty-five million, five hundred fifty-six thousand, seven hundred twenty-one".