999999416386561 has 2 divisors, whose sum is σ = 999999416386562. Its totient is φ = 999999416386560.

The previous prime is 999999416386499. The next prime is 999999416386573. The reversal of 999999416386561 is 165683614999999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 979661517207025 + 20337899179536 = 31299545^2 + 4509756^2 .

It is a cyclic number.

It is not a de Polignac number, because 999999416386561 - 2³⁷ = 999861977433089 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 999999416386561.

It is not a weakly prime, because it can be changed into another prime (999999416386591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499999708193280 + 499999708193281.

It is an arithmetic number, because the mean of its divisors is an integer number (499999708193281).

Almost surely, 2^{999999416386561} is an apocalyptic number.

It is an amenable number.

999999416386561 is a deficient number, since it is larger than the sum of its proper divisors (1).

999999416386561 is an equidigital number, since it uses as much as digits as its factorization.

999999416386561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 55099802880, while the sum is 94.

The spelling of 999999416386561 in words is "nine hundred ninety-nine trillion, nine hundred ninety-nine billion, four hundred sixteen million, three hundred eighty-six thousand, five hundred sixty-one".