1213678581809 has 2 divisors, whose sum is σ = 1213678581810. Its totient is φ = 1213678581808.

The previous prime is 1213678581769. The next prime is 1213678581847. The reversal of 1213678581809 is 9081858763121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 895915254784 + 317763327025 = 946528^2 + 563705^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1213678581809 is a prime.

It is not a weakly prime, because it can be changed into another prime (1213678581109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606839290904 + 606839290905.

It is an arithmetic number, because the mean of its divisors is an integer number (606839290905).

Almost surely, 2^{1213678581809} is an apocalyptic number.

It is an amenable number.

1213678581809 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213678581809 is an equidigital number, since it uses as much as digits as its factorization.

1213678581809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5806080, while the sum is 59.

The spelling of 1213678581809 in words is "one trillion, two hundred thirteen billion, six hundred seventy-eight million, five hundred eighty-one thousand, eight hundred nine".