99766561 has 2 divisors, whose sum is σ = 99766562. Its totient is φ = 99766560.

The previous prime is 99766553. The next prime is 99766577. The reversal of 99766561 is 16566799.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58614336 + 41152225 = 7656^2 + 6415^2 .

It is an emirp because it is prime and its reverse (16566799) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99766561 - 2³ = 99766553 is a prime.

It is not a weakly prime, because it can be changed into another prime (99766531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49883280 + 49883281.

It is an arithmetic number, because the mean of its divisors is an integer number (49883281).

Almost surely, 2^99766561 is an apocalyptic number.

It is an amenable number.

99766561 is a deficient number, since it is larger than the sum of its proper divisors (1).

99766561 is an equidigital number, since it uses as much as digits as its factorization.

99766561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 612360, while the sum is 49.

The square root of 99766561 is about 9988.3212303169. The cubic root of 99766561 is about 463.7974260025.

The spelling of 99766561 in words is "ninety-nine million, seven hundred sixty-six thousand, five hundred sixty-one".