1864908221609 has 2 divisors, whose sum is σ = 1864908221610. Its totient is φ = 1864908221608.

The previous prime is 1864908221593. The next prime is 1864908221641. The reversal of 1864908221609 is 9061228094681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1726062557209 + 138845664400 = 1313797^2 + 372620^2 .

It is a cyclic number.

It is not a de Polignac number, because 1864908221609 - 2⁴ = 1864908221593 is a prime.

It is a super-3 number, since 3×1864908221609³ (a number of 38 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (1864908221689) 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, 932454110804 + 932454110805.

It is an arithmetic number, because the mean of its divisors is an integer number (932454110805).

Almost surely, 2^{1864908221609} is an apocalyptic number.

It is an amenable number.

1864908221609 is a deficient number, since it is larger than the sum of its proper divisors (1).

1864908221609 is an equidigital number, since it uses as much as digits as its factorization.

1864908221609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2985984, while the sum is 56.

The spelling of 1864908221609 in words is "one trillion, eight hundred sixty-four billion, nine hundred eight million, two hundred twenty-one thousand, six hundred nine".