194218561 has 2 divisors, whose sum is σ = 194218562. Its totient is φ = 194218560.

The previous prime is 194218543. The next prime is 194218603. The reversal of 194218561 is 165812491.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 144600625 + 49617936 = 12025^2 + 7044^2 .

It is a cyclic number.

It is not a de Polignac number, because 194218561 - 2¹³ = 194210369 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 194218561.

It is not a weakly prime, because it can be changed into another prime (194218961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97109280 + 97109281.

It is an arithmetic number, because the mean of its divisors is an integer number (97109281).

Almost surely, 2^194218561 is an apocalyptic number.

It is an amenable number.

194218561 is a deficient number, since it is larger than the sum of its proper divisors (1).

194218561 is an equidigital number, since it uses as much as digits as its factorization.

194218561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17280, while the sum is 37.

The square root of 194218561 is about 13936.2319512844. The cubic root of 194218561 is about 579.1133509732.

It can be divided in two parts, 1942 and 18561, that added together give a triangular number (20503 = T₂₀₂).

The spelling of 194218561 in words is "one hundred ninety-four million, two hundred eighteen thousand, five hundred sixty-one".