100016561 has 2 divisors, whose sum is σ = 100016562. Its totient is φ = 100016560.

The previous prime is 100016537. The next prime is 100016569. The reversal of 100016561 is 165610001.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52475536 + 47541025 = 7244^2 + 6895^2 .

It is a cyclic number.

It is not a de Polignac number, because 100016561 - 2¹⁰ = 100015537 is a prime.

It is not a weakly prime, because it can be changed into another prime (100016569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50008280 + 50008281.

It is an arithmetic number, because the mean of its divisors is an integer number (50008281).

Almost surely, 2^100016561 is an apocalyptic number.

It is an amenable number.

100016561 is a deficient number, since it is larger than the sum of its proper divisors (1).

100016561 is an equidigital number, since it uses as much as digits as its factorization.

100016561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 100016561 is about 10000.8280157195. The cubic root of 100016561 is about 464.1845050645.

Adding to 100016561 its reverse (165610001), we get a palindrome (265626562).

The spelling of 100016561 in words is "one hundred million, sixteen thousand, five hundred sixty-one".