11812557817 has 2 divisors, whose sum is σ = 11812557818. Its totient is φ = 11812557816.

The previous prime is 11812557761. The next prime is 11812557839. The reversal of 11812557817 is 71875521811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11273342976 + 539214841 = 106176^2 + 23221^2 .

It is a cyclic number.

It is not a de Polignac number, because 11812557817 - 2⁷ = 11812557689 is a prime.

It is not a weakly prime, because it can be changed into another prime (11812557917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5906278908 + 5906278909.

It is an arithmetic number, because the mean of its divisors is an integer number (5906278909).

Almost surely, 2^11812557817 is an apocalyptic number.

It is an amenable number.

11812557817 is a deficient number, since it is larger than the sum of its proper divisors (1).

11812557817 is an equidigital number, since it uses as much as digits as its factorization.

11812557817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 156800, while the sum is 46.

The spelling of 11812557817 in words is "eleven billion, eight hundred twelve million, five hundred fifty-seven thousand, eight hundred seventeen".