21750726617 has 2 divisors, whose sum is σ = 21750726618. Its totient is φ = 21750726616.

The previous prime is 21750726589. The next prime is 21750726661. The reversal of 21750726617 is 71662705712.

It is an a-pointer prime, because the next prime (21750726661) can be obtained adding 21750726617 to its sum of digits (44).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20997169216 + 753557401 = 144904^2 + 27451^2 .

It is a cyclic number.

It is not a de Polignac number, because 21750726617 - 2¹⁰ = 21750725593 is a prime.

It is not a weakly prime, because it can be changed into another prime (21750726667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10875363308 + 10875363309.

It is an arithmetic number, because the mean of its divisors is an integer number (10875363309).

Almost surely, 2^21750726617 is an apocalyptic number.

It is an amenable number.

21750726617 is a deficient number, since it is larger than the sum of its proper divisors (1).

21750726617 is an equidigital number, since it uses as much as digits as its factorization.

21750726617 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 246960, while the sum is 44.

The spelling of 21750726617 in words is "twenty-one billion, seven hundred fifty million, seven hundred twenty-six thousand, six hundred seventeen".