1217308861 has 2 divisors, whose sum is σ = 1217308862. Its totient is φ = 1217308860.

The previous prime is 1217308831. The next prime is 1217308871. The reversal of 1217308861 is 1688037121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1054235961 + 163072900 = 32469^2 + 12770^2 .

It is a cyclic number.

It is not a de Polignac number, because 1217308861 - 2⁹ = 1217308349 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1217308861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1217308831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608654430 + 608654431.

It is an arithmetic number, because the mean of its divisors is an integer number (608654431).

Almost surely, 2^1217308861 is an apocalyptic number.

It is an amenable number.

1217308861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1217308861 is an equidigital number, since it uses as much as digits as its factorization.

1217308861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 1217308861 is about 34889.9535826576. The cubic root of 1217308861 is about 1067.7434790618.

It can be divided in two parts, 1217 and 308861, that added together give a triangular number (310078 = T₇₈₇).

The spelling of 1217308861 in words is "one billion, two hundred seventeen million, three hundred eight thousand, eight hundred sixty-one".