16861388617 has 2 divisors, whose sum is σ = 16861388618. Its totient is φ = 16861388616.

The previous prime is 16861388567. The next prime is 16861388623. The reversal of 16861388617 is 71688316861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10820368441 + 6041020176 = 104021^2 + 77724^2 .

It is a cyclic number.

It is not a de Polignac number, because 16861388617 - 2¹⁹ = 16860864329 is a prime.

It is a super-3 number, since 3×16861388617³ (a number of 32 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (16861388417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8430694308 + 8430694309.

It is an arithmetic number, because the mean of its divisors is an integer number (8430694309).

Almost surely, 2^16861388617 is an apocalyptic number.

It is an amenable number.

16861388617 is a deficient number, since it is larger than the sum of its proper divisors (1).

16861388617 is an equidigital number, since it uses as much as digits as its factorization.

16861388617 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2322432, while the sum is 55.

The spelling of 16861388617 in words is "sixteen billion, eight hundred sixty-one million, three hundred eighty-eight thousand, six hundred seventeen".