209861435401 has 2 divisors, whose sum is σ = 209861435402. Its totient is φ = 209861435400.

The previous prime is 209861435383. The next prime is 209861435429. The reversal of 209861435401 is 104534168902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 209429793225 + 431642176 = 457635^2 + 20776^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-209861435401 is a prime.

It is not a weakly prime, because it can be changed into another prime (209861436401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104930717700 + 104930717701.

It is an arithmetic number, because the mean of its divisors is an integer number (104930717701).

Almost surely, 2^209861435401 is an apocalyptic number.

It is an amenable number.

209861435401 is a deficient number, since it is larger than the sum of its proper divisors (1).

209861435401 is an equidigital number, since it uses as much as digits as its factorization.

209861435401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 207360, while the sum is 43.

The spelling of 209861435401 in words is "two hundred nine billion, eight hundred sixty-one million, four hundred thirty-five thousand, four hundred one".