215221620689 has 2 divisors, whose sum is σ = 215221620690. Its totient is φ = 215221620688.

The previous prime is 215221620617. The next prime is 215221620697. The reversal of 215221620689 is 986026122512.

215221620689 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 213980256400 + 1241364289 = 462580^2 + 35233^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-215221620689 is a prime.

It is not a weakly prime, because it can be changed into another prime (215221623689) 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, 107610810344 + 107610810345.

It is an arithmetic number, because the mean of its divisors is an integer number (107610810345).

Almost surely, 2^215221620689 is an apocalyptic number.

It is an amenable number.

215221620689 is a deficient number, since it is larger than the sum of its proper divisors (1).

215221620689 is an equidigital number, since it uses as much as digits as its factorization.

215221620689 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 207360, while the sum is 44.

The spelling of 215221620689 in words is "two hundred fifteen billion, two hundred twenty-one million, six hundred twenty thousand, six hundred eighty-nine".